Wear yourself out during the day. Force yourself to take up physical activity - running, swimming, weight lifting. Try and stay active and moving throughout the day.
Also, try meditating. It used to take me hours to fall asleep, because I'd simply sit there and think, think about everything. When you can control your thoughts, and simply think of nothing - just 'be' - it's much easier to sleep (and to live!).
Don't take medication - do it for yourself.