I know what you mean, Candice. I'm not in college (didn't go because of health reasons, so I do courses at home), but in high school I had the same problems. Swamped with work, worrying about how and when it was going to get done, etc. But I was always one of those people who can't focus on anything else when they know something has to be done. If I knew I had a paper due in three days, I'd get it done in the first day so the rest of the time was my own. And what I couldn't get done, my teachers usually gave me an extention on. So talk to your instructors, they may be a bit easier on you when it comes to deadlines.
As far as stress relief, I agree with Sean...about both methods, actually *ahem*, but more about the video game. That's what I do when I can't seem to focus or when I'm so worn from looking at a med book or a computer screen that I'm going to go nuts. Resident Evil 4 is usually my game of choice for this (yay for exploding zombies!) or a racing game like Jak X (where you can blow every other car on the track into pieces).
However, if video games aren't your thing, reading is just as good. Sometimes to unwind I'll curl up in a nice hot bath with a good book. Or my iPod, whichever. Music works wonders for stress relief. Or just get yourself out of the house and go do something fun with a friend or your guy. Napping works, too...I'm good at that *lol* Just remember that your health is more important than anything else. Don't let yourself decline because of school work. A term paper isn't worth getting sick over, and hopefully your teachers will feel the same way.