Painful sex 33 weeks...TMI

Okay, I'm 33 weeks and my hubby and I haven't had sex much lately because I just feel kind of bleh. This morning we were messing around and decided to have sex. I was on top and as soon as he went in it hurt...like a burning/stinging feeling. He said he could feel something unusual when I'd move and when I got up he was covered in watery white discharge. Sorry I know this is all tmi. And now I'm cramping and have horrible diarrhea. Something feels weird up there, too. Could this just be normal end of pregnancy stuff or should I be worried?