Like a rock

Hi everyone.

I'm 19weeks now, and I have to hold my stomach since... I feel like day 1 haha. Of course it's worse now with the bump, everytime I'm walking I have to help my stomach hold everything or at least that's the feeling I have. I bought a maternity support band for that and it works wonders. Maybe I just have weak muscles? I don't know. But, on Tuesday night my belly started feeling way harder than usual, and in the end I couldn't stand anymore, I dropped to the floor, I felt like the rock that was my uterus was going to come out of me somehow. And that was a very strange feeling. I had no pain, nor bleeding so I'm not stressing about it, I'm just waiting for the OB to tell me everything is fine but I would love to know if this happens to any of you?