39weeks + 1 day & feeling crummy

FTM and I didn’t sleep at all last night, maybe an hour or two in total. When I eventually woke up for the day, I just felt off. Very achy, mild to moderate cramps and like a bellyache kinda feeling; oh and very heavy in the lower belly area. I’m already 3 cm and 90% effaced, our doctor said it could be any day. I don’t know if it’s even possible to sense labor contractions before they begin, but I feel like these feelings are the beginning and that at some point today I’m going to start feeling those strong painful ones my doctor said I would. Has anyone ever experienced this before?