Sounds like your body is having practice contractions. I've been having mild contractions for five days and am 39+2 but it never builds into labor. When is your next appt? You can always mention it to your OB or MW when you get checked.
When you can time the contractions regularly, you're in labor. Regular being the key word. That's when u go to the hospital. But if for any reason, the pain becomes unbearable and your water has broken, go anyway. Chances are, labor will start n contractions will begin to come regularly