back labor

Okay. I've been up since maybe 3 o clock with what I think is back labor. I'm 36 weeks and 2 days. The pain is lasting maybe 2-3 min. And it wears off which I'm able to doze off for maybe about 15 mins and then the cycle repeats. I've already been in the ER twice and sent home due to contractions. But i hadnt dilated past two cm. Idk if I'm having uterine contractions or not. Not sure if they are there or not cause I'm saying so much attention to the back pain.