AFTER SEX! Am I hurting my baby?

I know that we all "get it on". But it never seems to fail, that after my SO and I are through love making, my baby seems to ball up really hard, and not move. She usually goes up higher than normal, and won't come down till the morning. Is this normal? This is my 3rd baby, and I've never had this happen before. Sometimes she's so hard and tight in a ball that it hurts me to move. I just want to know if anyone has this happen as well, and if they've brought it up to a doctor? Is it ok? BTW: I'm 23w2d with baby girl #3 Thanks in advance for your help :)