You could try valerian root or Vervain, I slipped a disc in my lower back a couple of years ago, Spent 4 days and nights on my living room floor sitting in the same possition or in the bath without any sleep at all.
It’s hard to sleep sitting and sleeping in the bath isn’t a good idea, after calling my doctor and being told to come down to the surgery and get stronger pain killers and asking what with a F@cking block of flats glued to my arse with gravity?
I hobbled through to the kitchen and had a rummage about, while the pain started to mount I found some Vervain and took quite a lot. It relaxed my muscles enough for me to get 6 glorious hours of sleep.
I woke up with a very dead leg from the nerve being trapped and I have to admit I hate doctors, a fact I was happy to share with my old ones but have kept quiet from my new ones.
But I did get some sleep, valerian is probably the best for getting you to sleep.
You could also try some relaxation techniques, a very simply one is to clench your hands and feet while you lie there then simply let them relax and pay attention to the process. It’s the same process of letting go that your whole body needs to learn.
Once you relax your hands an feet, just relax all the other parts of your body start at your feet then your ankles then lower legs and so on and so forth. Once you get to relaxing your head you will probably find that you tongue is at the top of your mouth, let it drop down.
Another technique is to focus on your breathing and simply direct it without forcing it, you should breath with your stomach and abdomin not your chest and it should be reasonably deep but relaxed. Another technique is to count or do a mantra, I LOVE HOOTERS, works for me.
Good luck with the sleeping