I'll second the melatonin. My d8 uses it to help her sleep (she has autism spectrum and some of these children have low melatonin). She has been able to go to sleep within about 30 minutes of the melatonin, and then has slept better throughout the night as well as she used to stay up late and wake up frequently through the night!
I've been having problems sleeping lately too and thanks to NoCode's suggestion, I think I will try using them as well (hadn't thought of that)!!! Karen