Has anyone ever had what they call irritable uterus???

I’m 21 weeks pregnant and did a follow up with my OB because a couple weeks ago I was at the ER due to severe stomach pain and they said that I had infection but we caught it early.

Well for a couple weeks now I’ve noticed at random times my uterus will get really hard and tight (especially when I have to pee really bad) but then after a little while it’ll relax again. So I asked my doctor about it today and she said “hopefully it’s a irritable uterus but if you notice a pattern in them then go to L&D and they’ll monitor you to make sure they aren’t real contractions”...... and I’ve been cramping more then normal these past few days so she said if I keep cramping she is going to check my cervix again. But what’s yalls story with a irritable uterus?? Did it cause the baby to come early??