Okay, so I am 27 w 2 d and this is my second child. I'm not considered to be high risk. Since about 4 this evening I started experiencing lower back cramps, it's been 5 1/2 hours now. It will cramp up to the point that I'll catch my breath a little and it will hold like that for 5-10 minutes then let loose. After that it aches for about a half hour and does it again. It is super uncomfortable, and a little painful at times. I've tried some super low heat, resting, and walking. Right now I'm sipping water pretty constantly to see if I'm dehydrated. The baby has been moving pretty regular and I haven't felt any low pressure or tightening, but I did have some diarrhea about the same time the cramps started. On a side note, my husband and I had sex earlier today. I'm just a little worried because this hasn't subsided for a number of hours now and I'm not sure if I should call the on call doctor or not. If it keeps happening I'll give them a call...any opinions or advice?