Early Contraction?

I'm a ftm, a day overdue, and no signs of labor yet, that I know of. I have gotten some Braxton Hicks though. Tonight I felt a pain in my lower back and my abdomen felt hard. It only lasted like a second, but I'm wondering if that could have been an early labor contraction. It wasn't too painful. I probably sound dumb for not knowing but I am curious! That was a while ago and haven't felt it again.