2nd Membrane sweep today, terrible back contractions?

I'm 38 weeks and 2 days today, and I had my second membrane sweep about 3 hours ago. I had one last thursday, and it didn't do anything really. I've had contractions for the last 2 weeks, and I was 1 centimeter and a half at my last app. now I'm almost 2. My OB still says she can't quite fit 2 fingers in, but she stretched me the best she could. After for about 2 and a half hours I had really bad contractions and horrible back pain, and I'm still getting back pain, and I feel not so much hungry as I do thirsty (my contractions were so bad I couldn't finish my dinner, I just drank fluids) Then I had a really good poop (sorry if tmi) then I peed, and that relieved some of the pressure I was having, but I'm still having back pain. My OB said that if my water was going to break today, while she was stretching, it probably would have happened, but after my first sweep, I didn't have any contractions or back pain like this. Will I go into labour soon??? or will my water break?? Mucus plug is gone for a few days now, might have gotten a little bit more earlier after I pooed, but most came out the other day. Any thoughts? opinions, suggestions? My OB said I should have a baby this week, but I'm not due till th 19th...whatdya think