Contractions or Braxton Hicks?

So for a few hours my stomach has begun to hurt constantly. But in the past 30 minutes it's gotten where it's constant but also intensifies for a few seconds then is the same intensity. I just had 2 that hurt so bad that it made me cry.. On a side note, my son is still moving and squirming around fine, but on Google it says I could still be experiencing preterm labor. has anyone else experienced this?? and was it preterm labor or just typical Braxton Hicks??

PS: I'm 31 weeks 3 days, first time being pregnant!!