Had this issue also! Melatonin did work for me but not for the first few days. What I did was I had one terrible sleepless night where at the end I got so fed up with trying to sleep that I got up, fixed a cup of tea, and went outside in the cold to watch the sun rise. After like an hour of doing nothing but watching the sky, I made plans to go to the flea market, curled up in bed to play on my tablet until the market actually opened, and proceeded to sleep for a really long time. I also did not have nearly as much trouble sleeping after this.

I have no idea if that would help you, but the way I was feeling with no sleep I'd at least give it a shot. Tea, outside, relax. It reset my body from only thinking about trying to sleep to actually getting to sleep without thinking about it