Contractions?

I'm 33 wks 2 days, me and my SO had sex for the first time in a while and now I think I'm having contractions. I was laying on the couch the first time and it was kinda painful. My Braxton hicks have been uncomfortable but not painful. The second one I was sitting up on the couch. It went around to my back both times. They were about 20 mins apart. Idk if I should go in or not cause I'm supposed to have my c section on the 21st of may.