[Aerich]

Ah, so you're getting the condescension now...

That's a bit tougher. You have to show them you have teeth. Next time one talks down to you, give it right back to him/her. Half in jest, but make sure the edge shows through. Just a couple sentences; enough to show them you won't be their doormat anytime they have nothing better to do. Alternately, you can sit down with one of them and make it clear about how you feel. Don't bare your soul, because you want whatever you say to get to the others.

And I second the good advice of Hierophant and T-D-C. If those dopes don't smarten up after you've dropped a few hints about how you feel, just relegate them to the "familiar acquaintances but not true friends" category. If you feel like a hanger-on when you're with them, spend as little time with them as possible.

It also sounds like the adjustment to college is a little rocky for you. Try not to stress about things. The best advice I can give is to actively try to make friends. Talk to people in your classes, in the cafeteria, and in your building. Make a special effort to talk to people who tend to keep to themselves. Usually those people are shy, but they often make far better friends than the hard-drinking social butterflies.