I know it’s a cliche but I find hot milk/chocolate really helps me sleep when I’m struggling to nod off. I’ve found the effectiveness depends on a couple of things, first full fat milk, semi skimmed or skimmed just don’t seem to work. Second is heat it slowly in a pan on the cooker, zapping it in the microwave doesn’t cut it. It’s apparently got something to do with the way the fats and protein denaturate when heated.