37 weeks along, pain in lower back and upper abdomen?

At my last doctors appointment (Tuesday) I was a "loose 1" and 65% effaced. My doctor said she would give me 2-3 weeks tops and then she said she thought I'd have a baby by then if not sooner. Last night, my back started hurting badly. And at 2:00 this morning I woke from a very deep sleep with sharp abdomen pains. The thing is, I'm almost positive it's NOT contractions. My tummy was tight when I was sitting up, but not rock hard and it relaxed when I laid down but any time I sat back up it would tighten, though again, not rock hard. Today I've been having abdominal cramps and constant back pain. I'm just trying to decide if I should call my dr.'s office (they will patch me through to the dr. on call since it's a holiday) or if I should wait until my appointment on Tuesday to call. I seem to call my dr. a lot because this is my first and I'm super paranoid all the time. I just want my baby to be okay. I am in a lot of pain and nothing seems to help. I thought I may be in false labor but nothing seems to make the pain stop. I've also gone to the bathroom and had a bowel movement about 6 or 7 times today. Anyone had this? Any advice?