Back pain at night

I'm only 19+3 and already experiencing back pain, making it hard to sleep at night. It goes away during the day, I think it's worse at night because I don't have as much lower back support when I need it. My belly isn't even that big yet, and I know the pain will get worse as I grow. Any ideas to help with this at night. I already have a body pillow, but it doesn't seem to help much. Thank you!