I like to put a pillow down and then jack my leg up sort of laying on my belly, the pillow keeps me from squishing everything and being uncomfortable. Also when side lying, ALWAYS put a pillow in-between your knees to align your spine properly. You can also put a pillow behind your back and switch between leaning forward, staying straight and leaning back to help change pressure at Your hips.
I’m 24 weeks and Unisom is the only thing thats given me a full night sleep through this entire pregnancy. I noticed I’m up and restless at 3 or 4 if I don’t take it.
You can sleep on your back without worry as long as you’re elevated or slightly angled off your right side. So you can either get a wedge pillow or prop a pillow under you. Ultimately, sleep is the most important in whatever way you can get it.