TMI. But need advice.

Okay, this is definitely tmi but I'm a bit worried. I'm usually constipated and only poop very little throughout the day. Well this morning I woke up and everything I eat just seems to pass trough me. No diarrhea, soft stools. I'm 21 weeks. I'm getting scared because I read online and I know I never should, but the internet is saying it can be labor but I'm barely going on 5 months. No pain or bleeding either. Is this normal? My OB said it was but I'd feel better hearing it from other ladies. Much appreciated, thank you.