Anyone have any tips to help me determine the difference?

I've been contracting since yesterday morning. They started out just light cramping, by last night they were a little more uncomfortable and I didn't sleep well due to it. This morning they were painful and seemed to start in my back and kind of come around to the front, i guess. I started timing them and am having 4-5 in an hour. The on call doctor at my office seemed to brush me off and said "Probably Braxton Hicks..." but I have pushed plenty of fluids and have been laying down all day and they are not going away...