Tyr and Bingo are right. You need to walk out on the limb, take the risks and get involved anyway you can. A lack of confidence seems to be the main thing holding you back. One little thing I'd add is not to wait. Not because you're going to be leaving soon or anything else. So what if you leave soon, at least it will be socializing experience. Like Tyr says, NO excuses.
At 20 I was similarly situated romantically, it will work out once you get to socializing and meeting people. There is nothing wrong with being a virgin. The cure is a desirable experience, so find a girl it will really be desirable with, not just a one-off check of a box, or a substitute for a relationship. Also consider dating sites, okcupid or something. There are girls out there in similar circumstances.
You have geeky pursuits - share them with others. Magic players are typically willing to teach others since they then have someone else to play with, someone else to attend tournaments. Comic shops that hold tournaments are especially willing to get you hooked. Not a great way of meeting girls, of course, but it can be one outlet for socializing. Even if you're terrible at something like Magic, most are pretty tolerant about it.
Also, don't beat yourself up too much when things don't go well.
I've only ever been to a single party at my college and that felt like a once-in-a-lifetime opportunity for somebody like me. It led to nothing.
Experience will help dispel this feeling. Parties generally result in nothing, except that you hopefully had a good time. I understand the hope that it will provide the big breakthrough and the launching pad for all future socialization (maybe even a girlfriend), but it generally doesn't happen that way.
Also, if people can't tell that you're having a good time - even if they like you - they are less likely to extend further invitations. You need to reach out to them, talk to people on facebook, stay in contact, be engaged when you do hang out.
For recreational activities, consider climbing/hiking - very big around eastern Tennessee anyways.
You're at that 'finding yourself' place. Either you sit around hoping something happens or you make it happen. It's great that you know what career you want. But when you finally do kiss a girl and you're on top of the world, you may well feel that she is 'the one,' since finding another would be so improbable. It's a normal feeling, but you cannot expect or rely on any single experience to be the fix you need. Enjoy each experience for what it is. You happiness has to come from something more than that.
Getting the confidence is hard, so listen to Bingo, let go of worrying and thinking and just go.