Melatonin? My friend Ruzz in an old blog, had good experiences with it. If you look around the date of that post you can see his general complaints about insomnia.

I also know from a different friend that there's an antidepressant that doesn't work well for depression (don't ask me, I don't understand it either) but does help to shut your brain off if you take it at bedtime. I can't think of the name right now. But he says it doesn't leave him with the hung over sleeping pill feeling in the morning. But try the melatonin first, if you haven't.