As a long term lifestyle solution, consider getting a dog. I used to have the same problem, could never sleep til 3, then overslept, had winter-funk type issues and was just out of whack.

The dog fixed it. Dog will let me hit the snooze button once or twice, but he gets fed at 8 AM and he knows what time that is. My dog forces me out of bed and keeps me on a fairly reasonable schedule, despite the fact that I'm naturally a night owl.

Funny thing about having a dog, you kind of sync your schedules without much effort on the human's part. The dog kind of makes it happen for you and keeps it even.

There are a lot of great dogs at the Seattle/King County Humane Society and Seattle Purebred Dog Rescue who would love to help you out.

http://www.seattlehumane.org/

http://www.spdrdogs.org/

Do you read or watch TV in bed? Or otherwise hang out in your bed before sleep?

What I've heard about mild cases of insomnia is to:
- Don't hang out in bed, only sleep in bed
- AM exercise is preferable to PM exercise
- Obvious caffeine avoidance in the PM, you could be more sensitive to it then you were in undergrad.

These would a few easy actions to take to try to induce an earlier bed time.

I feel your pain though. I currently work a second shift work schedule, M-F I do not need an alarm clock, Saturday and Sunday I do.

And spending all day and all night in the exact same artificially lit environment, emotionally 3am is just the same as 9am -- nice inside and only wanting to go outside when I need to.

If you're not too inconvenienced by your sleep schedule, you could try waiting out February to see what March brings. Our days should be noticeably longer and the morning birds noticeably louder then.

If you do want to go the alarm clock route to change your schedule now, I'd suggest one of those ease you into being awake alarm clocks. I've got an app for my phone, Sleep as an Android. It's more like your body eased you out of sleep than a loud noise interrupting your sleep, which for me just makes me want to sleep more out of spite.
[which is very easy to do if you don't really have to be awake AND you know you can stay up late with no repercussion]

Once your sleep/wake schedule is out of synchrony it does take some work to bring it back into a more normal pattern. Day/night rhythms are always harder to recognize in the dead of winter where it gets dark so early and light so late. We are on the side of the winter solstice where days are lengthening but for the immediate time it is still fairly lopsided to the darker side. But just as pulling a late or all-nighter can be stressful when you have a good day/night slumber pattern, so may be getting back to that now that you have an alternate cycle in process. I want to bring your attention to a number of factors that can affect your sleep/wake cycles and make a suggestion on how to get back on a more conventional track.

Forcing yourself to rise is difficult to do, especially if it is going to put you at a situational deficit for the short window of time. Consider how you are winding down the day to get to sleep in the first place. Sometimes people try going from high speed activity to bed and find getting relaxed for sleep is something they are doing in their bed. Crawling into bed ready for sleep feeling weary and ready to rest is the best scenario, so getting to the point to approach that moment is important. You can wind down the sensory impacts of loud music, bright lights, television by lowering volumes, using lamp dimmers and turning to a period of reading for enjoyment. Enjoy a shower or bath for relaxing and change into sleep clothes and have a warm drink of something without caffeine or alcohol. It isn't silly to have a real plan to how you will eventually get to bed. When reclined in bed use some relaxation techniques to systematically tense and relax various parts of your body. Think about pleasant times and places, use some internal affirmations about being sleepy and enjoying your sleep and dreams, breathing exercises for calming yourself can help. All of these techniques will take some research and learning to find out how to do them and what works for you.

During your awake time in the day make sure you are getting enough light in your environment. A trip to Ikea or thrift stores can be easy ways to buy more lamps and brighten up your home during dark dreary days. Getting outside for even muted daylight is very healthy. On the tech side you can purchase artificial dawn generators/timers that hook up to a light where you sleep and slowly raise the light level so your eyes and brain register a "dawn" waking experience.

Also an aside about inside air quality - be sure to air out your living space regularly and look to eliminate sources of molds and mildew (that can really stress your immune system and tire you). On the other front if you are getting static electricity shocks from walking around your place the relative humidity is too low for good respiratory health and you need to get more moisture in the air.

Because you are on medication your off-norm schedule is also probably affecting your mealtimes and perhaps the time of day you take your medications which can affect your brain cycles of wakefulness.

As you plan to normalize your sleep/wake schedule try to make the change gradual so that you are only working on earlier to bed times and wake times that change by 30 or even less (maybe more) minutes at a time. You will be more successful at moving your brain and energy cycles with small nudges (your success will tell you what interval to use).

I think you shouldn't try to force yourself to wake by a certain time, but it sounds like you're not enjoying falling asleep. I've had sleeping problems my entire life; often I can't fall asleep until early morning (like 4 or 5am) because I can't stop thinking or worrying - then I'll sleep really late and miss appointments, be late for class or work, etc. It's always worse this time of year. Even though I'm only sleeping 8 hours and it feels like I'm letting my body do what it wants to, I do notice that I feel better - mentally and physically - when I am on a more "normal" sleep pattern.

Some things that help me:

I have a lamp with fairly bright bulbs attached to a dawn simulator alarm clock - it has a sound alarm too but I don't use it. It gradually brightens my bedroom in the morning, and can also be used to gradually dim at night which helps stimulate natural melatonin. I like it better than the light box I tried, even though it's not the same "lux" value. There's some good info at Light Therapy for Depression, and this circadian rhythm questionnaire can help you figure out what time is best for you to start morning light exposure if you're interested.

I also use Gentle Alarm for Android. Much better than a blaring alarm clock when you need to get up. Gentle Alarm has a setting that makes me do a mini puzzle in order to turn the alarm off, so I don't just keep hitting the snooze button.

Eating a breakfast with protein no later than 10am, and eating regular meals throughout the day really helps. I try to not eat at least an hour before I go to sleep.

I take my medication when I get up in the morning, because it has a stimulant effect and it can interfere with my sleep if I take it too late. Same thing with caffeine.

Exercise - either vigorous or a relaxing walk - during the day really helps. Even in the winter when it's grey there is still a lot of light around noon, so I'll go for a walk then when I can. I can't exercise any later than 5pm or I'll have a hard time relaxing at night.

Regular relaxation - taking short relaxation breaks throughout the day, like walking somewhere or stretching, help me not get too "amped up." I'm also supposed to try something like relaxation breathing or stretching as part of my sleep hygeine, but I usually just read.

Not staring at a computer or TV screen for at least an hour before I go to bed helps, and I have F.lux on my computer which changes the monitor settings so it's not so bright at night.

I used to fall asleep with the radio on a lot too, sometimes the TV. If you need some background noise try relaxing music, nature sounds, guided meditations (corny but as effective as the BBC), or use a sleep timer on the radio so it's not on all night. Even though the sound helps you fall asleep it supposedly will interfere with your deep sleep cycle, which can have repercussions on mood.

When I get really off track I do take Ambien or another sleeping pill, and my doctor says it's better to do that and get good sleep than get back on a bad cycle. When I'm good about my daily schedule I find that I naturally get sleepy around 11 and look forward to going to sleep, instead of wondering how long I'll be laying there trying to fall asleep.

I'm coming from a slightly different place, I'm bipolar type II, but my doctor absolutely cracks the whip as far as my sleep schedule goes. He says that it's essential as far a maintaining mental health. I do my best to go to bed at the same time every night. And, no matter what, ABSOLUTELY NO NAPPING DURING THE DAY. When I sometimes slip and fall into a schedule like yours I have to get myself to set my alarm and get up no matter how tired I am. You're only miserable for the first day or two and then you're naturally falling asleep earlier.

I believe that some have suggested a light box. I didn't have any luck with it, but it does seem to work for some. What I wanted to mention about that is before investing in one I was able to rent one by the month through the hospital that my doctor was affiliated with. You may want to find out if that's a possibility for you.

The most important thing I wanted to say is that if my doctor is correct, and he does seem to know what he's doing, then your current sleep schedule is not your body doing what it seems to want to do and this may be contributing to your mood disorder.

I wouldn't worry about the sleep hours if you are getting decent sleep. But for the seasonal depression, a half hour or more spent in daylight (I go for long walks to achieve this) will work wonders. Even on cloudy days.

I'm a big fan of winter hibernation. If it's not causing a problem and you are feeling rested, don't worry about it. If you want some help with the overthinking, mindfulness practices have a lot of other benefits as well. I like to practice tai chi and chi kung before bed, I find it helps me shift down into relaxation mode. Lot's of people have similar benefits with yoga as well.

Couple of simple suggestions here:
I find it helps if I drink a small glass of milk.
Some prefer warm milk.
But I find what really helps me is to read a prose book, paperback or otherwise, that I'm really enjoying. Do a couple of chapters while curled up in the couch or your easy chair, with no other distractions or noise. I find I get sleepy within about 20 minutes to a half an hour. Try it.