Contractions?

I'm 39 weeks 3 days, and think I am experiencing comtractions. They woke me up last night, quite painful, but I didn't think anything of It. They have continued today. I called the OB and told them they weren't too bad (I'm not doubled over or anything), and they told me to drink some water as I could be dehydrated (very possible). It's been over an hour and I still have the tightening in my stomach, should I call back?