Gush of water during sex?

Leann
Me and my SO was having sex a couple nights ago, I was on top and we were going pretty rough. Well out of no where there was this huge gush of water or liquid or something. It WAS NOT pee. I know what peeing feels like, and it wasn't that. Idk what it was. At first I thought it was my water breaking (I'm 37 weeks pregnant tomorrow) but I haven't had any contractions since then or any other leakage so I'm assuming it wasn't that. Any ideas on what it could be?