Could this be contractions?

All day today, I been feeling my uterus tighten but no pain or pressure with it. It always starts from the top and works it's way down, and last for about 45 seconds to a min, and comes about every 15-20 mins. I've been having mucus discharge with blood, every time I go to the bathroom, along with pain in my back that comes and goes and a constant pain/aching in both my legs so bad I can barley walk, but when I'm able to walk I get this sharp pain in my ladies parts. I'm 36+2 today, I didn't experience this with my first( had him 9 weeks early) could this be true contractions? Or just Braxton's?