Intense pain after sex!!

This is going to be hard to explain so please bear with me. My husband and I have been ttc for about 8 months now and every once in a while after we finish having sex I get this intense, sharp shooting pain that comes in waves. It makes my whole body tense up, my toes curl, I can't move let alone walk or stand up straight. It doesn't feel like menstrual cramps and the location is a little bit lower than regular cramps are. They are INTENSE! This is the second time it's happened in our 7 months of trying so this is not a normal occurrence but it is a little concerning and just weird. The only pain I can relate it to is what I remember of a ruptured ovarian cyst that became infected when I was a teenager but obviously that pain didnt go away until I had surgery. Could it be sex causing a cyst to rupture? Idk.... any ideas? Can anyone relate to this??

Thanks in advance!