Lower abdomen pain after sex. Normal? Help please!

Destiny

I’m 24 weeks pregnant with baby #2. My husband and I have sex fairly often. Tonight after I had an orgasm my lower stomach started killing me. I didn’t make my husband stop until he got off. But after that it got even worse. Not really vaginal pain. Just in my lower stomach. It feels like cramps and my stomach is a lot harder than usual. I didn’t have sex hardly with my first child. I don’t know if this is normal.