Labor?

Can you be in the first stages of labor and have back contractions that stop and then come back? The other night I had one back contraction. The next day when after I pooped I started having back contractions that wrapped around my front that were close together and they stopped. Today I bent over and started having them again and cramps. They were constant, one right after the other. I had another one when I was laying down. I have pressure in my butt and I can't poop. I'm 36 weeks and 4 days pregnant. Im a first time mom. I know first stage of labor can take 12 hours. I'm just trying to figure out what this is. I haven't lost my mucus plug yet and my water hasn't broke. I have cervix pains and I also have cramps up front when the baby moves. Please help!