I recently started taking 1.5mg melatonin if I feel like shit before bed, or if I'm really tired, or of for some reason I expect not to sleep well. It helps quite a bit I think, I usually fall right asleep pretty fast if I take it.

I recommend it. But don't abuse it very often. And don't buy the expensive stuff. I think I paid like 15 euro for a pack of 60 tablets of 3mg that I bite half from.