stomach tightness and Braxton hicks

I am 34+4 pregnant and after eating and laying down for a bit I started to get Braxton hicks followed by stomach tightness. The tightness is around my belly and my belly is hard! I am now trying to go to the bathroom and it hurts as I have been constipated for a few days.any advice on this at all? I just want to make sure I'm not going through pre labor.