They make "nighttime" hand braces for carpal tunnel syndrome. They are soft and most have padded or beanbag material in the palms. Designed to keep your fingers relatively straight. I found they helped keep my fingers from hurting so much, clenching softness is much better.
I also sleep with a large body pillow. I sleep on my side, pillow between my legs and arms. Everything is supported, padded, and comfy as I can get. Solved a lot of pain caused by my body parts pressing on each other (knees/ankles are not padded!) and pain/numbness caused by arms/legs "drooping" when side sleeping.
I did a lot of teeth grinding when I was younger. Actually wore down some tooth surfaces. I wore a mouth guard, created by my dentist, for years. I was told it was a "stress" issue, and had to give up all caffeine. After a lot of 'meditative' solutions that didn't work (type A personality), the solution for me was a gentle Pilates workout/stretching routine every night about 2 hours before bed. Apparently, I needed to bleed off some of my daily frustrations and misery before bed...
Hang in there...