Sounds like Braxton Hicks to me, I am 39 weeks +4 days and i've been having that exact thing for over a month, consulted my doctor and even went to the birthing centre they monitored me and sent me home, even had them as close as 3 minutes apart and so tight they took my breath away, you'll know when they're the real deal, they get incredibly painful and grow in pain, and wouldn't have stopped to let you sleep! All good things though, means your body is preparing and working
That's labor. I had it and it worsened when they broke my water.
You could always call Drs office and see what they say.
Hmm I thought of Braxton hicks as a possibility too but I just didn't think they were supposed to consistently last for 20 hours and counting!