Contractions or baby stretching out??

I keep getting this hardening in my belly (obvi) and I’ve always thought it was just the baby stretching out or like balling up. It’s pretty uncomfortable and usually takes a minute to go away, but it hasn’t really been painful. I also know that contractions are supposed to make your belly feel like a rock too...so I’m wondering with it happening more often now if it may just be contractions? I’m 38 weeks today, so I would not be complaining if they were!