Okay ladies, can anyone help me out?

I've had constant back pains for my entire pregnancy but for the past two days it's been unbearable! It's ranging in the mid to lower back and WON'T go away! It feels like someone is taking a sledge hammer and just hitting me as hard as they can! Then it turns into a really dull spasm like feeling... I've taken Tylenol, used a heating pad, taken a hot bath, changed positions, got on my hands and knees, swimming, and pretty much EVERYTHING else I can think of to try to alleviate the pain and NOTHING has helped! I am almost 37 weeks with a breech baby boy.. can someone please enlighten me on some other options that might help? Could I be experiencing back labor?? TYIA