Pregnancy sex aftermath, is it normal?

I had sex today after a long while without having it and at first I’m ok just feeling normal. Then I randomly( my bf wakes me up to look at something on my phone he’s been waiting for) wake up at 1 am. Out of nowhere I get cramps and pressure in my pelvis. I thought I managed to escape the cramps since this is my 2nd pregnancy and in my last one I cramped on the day of my missed period but this is 3 days passed my period now.

This lasts for about an hour and have subsided thankfully. But it was not comfortable at all. Then it feels like I have to poop but nothing comes out. Is this the result of sex or just is it pregnancy symptoms?