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.