So glad you'll be able to speak with your doctor tomorrow, will be thinking of you.
In my case, the abdomen pain did come and go slightly: I first felt it around 11am, it came on suddenly and severely. I called my OB right away but, by the time she called back (about an hour) it had subsided into a dull ache. It continued to ache until around 5 and then came back in full force. It stayed that way until I left L&D and the ER (with a diagnosis of possible heartburn or gallstones...) around midnight. It was just a dull ache the next morning when I was admitted into the hospital and then I never felt it again. I have heard other people say the exact opposite though so, maybe it's different for everyone?
Thinking of you,
Zachary James, 7/22/03-7/27/03, born at 26wks - severe pe