Back Pain

I've been using my pillows, sleeping on my left side, doing my stretches, my best to keep good posture, and still exercise while taking it easy. But at 15+3 now my back is KILLING ME!

Like by the end of the day yesterday I was literally in tears and just broke down sobbing on my husband... who very perplexed gave me a bit of a back rub.

I think it's so sore because I am carrying fairly low. But that doesn't make the pain any better. What suggestions do others have for staying on top of back pain. I haven't had much for other symptoms bit I am also trying not to worry or take myself to the hospital.