Congratulations on your success at school! It doesn't sound like you're a "loser" or have bad luck to me, it just sounds like you're picky and for the most part focused on other things besides romance. There's nothing wrong with that, although I can understand why you'd feel frustrated. I had a friend who was in your situation at that age, and what it came down to was she was just holding out for the right guy. But seeing all her friends in relationships made it tough.
I don't think making out with guys you're not attracted to is the answer. Why not just accept that this is going to take a bit of time? I know it doesn't seem like it, but 21 is way too young to start feeling desperate. Still, it sounds like you mostly hang around women. A mostly-female campus is great for keeping you focused on your studies (and worth it, I think), but not great for meeting a wide variety of guys. Once you're off to grad school, you'll likely find more of a mix.
In the meantime, stop thinking of yourself as a loser. It's not true, and guys will pick up on it and see it as a turn off. You want to feel confident in yourself and curious and open to others. It's possible that some guys are intimidated by your intelligence and achievements -- too bad for them. Seek out smart men and build friendships based on shared interests, like kitschnsync said. Eventually you will find men who find your intelligence sexy and your discerning attitude toward other guys an asset. Mostly, just don't buy in to that "poor me, guys don't like me, I'm such a loser" attitude. Identify yourself with your successes, and accept that you've chosen to wait until the right guy comes along. There's no need to feel inadequate about that.
One other thing: physical confidence is always attractive. Learning how to dance or getting involved with sports are great ways to have fun and meet lots of guys in a casual, low-stakes setting.