Back pain! ☹️

I am 21 weeks with di/di twins. I am having absolutely awful back pain, and it's making it impossible for me to sleep at night. I take Benedryl nightly for sleep and to help with allergies, but I just can't seem to get to a point where I get any kind of sleep. I have a pregnancy pillow which hasn't helped much, and also have small pillows I keep pressed against my back to try to help relieve some pain. Any of you ladies have any advice? Tylenol doesn't help much, and I go to a chiropractor once a week. I know it's only the beginning, but with a 5 year old, I NEED some kind of sleep! Haha!