I am having that problem too but I'm only 30 weeks
I wouldn't worry much about it but keep hydrated cause I have been having the same problem but for like 1 wk. I know tmi but im still having loose bowel movements. I think it has something to do with your body clearing out and getting ready for Labour.
They say diarrhea is a sign of labor but I had it at 37 weeks , was told it could be something I ate or simply just baby not applying much pressure on them anymore making my bowel movement easier to pass . Cramping can just be braxton hicks . If you can time them try to do that otherwise it does t sound like anything concerning .