gochiefs, I hope you're appreciating all the terrific advice you're getting on this board, because we all very easily could be busting your balls over this. If a bunch of complete strangers with a penchant for smaque are willing to cut you some slack, why do you thinks folks who know you -- and invite you to their parties -- won't?
I didn't start socializing big time until I was a junior or senior in high school. I just started going to parties, would sit back with a friend or two, sometimes alone, with a beer and without fail somebody would come up and talk to me. Often it was a girl -- there are a lot of girls out there who are outgoing (and/or liquored up) and just like to talk to guys at parties. Doesn't mean you're going to get laid, but you gotta start somewhere.
When I hit college, I was a completely different person at 18 than I was at 16. College was awesome. I met a whole bunch of great people of all different backgrounds. I'd talk sports with guys who were jocks, or brains, or geeks. Didn't matter -- we had one thing in common. College wasn't clique-ish like high school. DO NOT WASTE WHAT'S LEFT OF YOUR COLLEGE DAYS. You will regret it for the rest of your life.
Get off your ass and go live some!