Possible early labor?

Im 37 weeks, the last two days ive had mild period like cramping and diarrhea... this morning i woke up just feeling like crap, nauseous headache and crampy. Then about an hour ago i started having contractions i think, they are painful like a bad period cramp they dont go away whether i walk sit lay down etc, but they are very inconsistent. The only thing i feel consistently is bad back pain? Heres whats going on right now... two weeks ago inwas only 1 cm dilated and baby low