Just thought I'd jump in here with a tip:

I used to have trouble falling asleep through my teens and early 20's too. I don't recommend using pills, especially things like melatonin. When you're young, your body should be producing plenty of melatonin already.

I recommend learning self-hypnosis. It's cheap (it's free actually), it's easy, it's safe, and it's effective if you practice it enough. There's tons of good books at Amazon for S.H. But a great intro for newbies is "The Idiot's Guide to Hypnosis."

Hope that helps.

Peace