Braxton hicks or contractions??

So I feel almost silly asking this, cause this is my 3rd pregnancy. But I have started to feel what feels like contractions. Its a tighening feeling in my stomach and in my lower back. Im going to be 19 weeks on monday. And i feel like this is too early for braxton hicks. I have drank plenty of water and laid down and they are still happening. Not sure what to think. Opinons? If they get too bad obviously i will go into the ER. But i am just unsure.