I woke up this morning with some intense cramping. So intense that I ran to the bathroom because I was certain I was having a miscarriage but there was no bleeding. It lasted for about two hours before subsiding. I called my OB and talked with one of the nurses and she said that it is fairly common if you are dehydrated to wake up with cramping. I searched all over the interwebs to find info on cramping without bleeding and I never heard any advice other than "it's normal to have cramping as long as you don't bleed heavily."
So, lesson learned: drink plenty of fluids and make sure to go to bed with some water. I have been drinking RRL/Nettle infusion this morning and it seems to be helping.