Maybe start of labor? Please comment opinions.

Brooklyn

I have been having mild contractions I’m pretty sure are Braxton Hicks for 3 days now. Well about 40 minutes ago I got this slow tightening starting from my back coming to the front. My stomach is rock hard while this happens. I have noticed them every 10 mins so far. Could this be the start of labor and should I really start timing them closely? They are actually taking my breath when they come are somewhat painful. I’m 35w 6days.