It is probably brackston hicks like funny mommy said. And that's a good sign your full term so if you want to try to have some sex and eat lots of spice and what jot you can help labor along :)
It's probably braxton hicks contractions. It's your body's way of practicing
Im due the same day :-) due date buddies :-) lol I've been feeling super tension in tummy and cramps along lower half for the past 2 days.. hopefully maybe soon for us :-)