I think it is a combo of missing hormones,
anxiety, other meds...? My gyn/onc wanted me to try benadryl before going to something else. I take 50mgs at bedtime. This has helped and I do sleep...eventually, but I still have issues. Anything that relaxes you is helpful - bath, music, yoga. A friend of mine gave me a soduku puzzle book and I find myself falling asleep sooner with that than I do with a book. You should talk to your dr. and see what he recommends.