Ive never felt braxton hicks before but I'm having really uncomfortable pains, I'm 31wks+6d, its like strong period cramps in my back then travels to the front. I can't tell if my stomach gets harder but my boyfriend says it does. Ive been having them for a little longer than 20mins now nd they come every 2-5 mins. Does this sound like braxton hicks, or should I be worried?