Contractions or BH?

I'm getting BH (I think) every few minutes for about an hour now and each time they take my breathe away. Some have lower back pain and others don't. I'm going to start timing them to see how far apart they are. But at this point I can't tell if it's a BH, contraction, or baby pushing against me. I'm 37w3d so still have a ways to go. Last one I had was at 10:21. It's now 10:24 and haven't had one just yet.