Potty during sex?

So lately whenever I have sex with my husband and we're doing doggy style I feel like taking a dump. (It's not through the butt hole). It never happened before. I've been feeling really stressed out. Might that be the reason why? Anybody else has had this happen before? It's making me not enjoy my time with my husband :( he said it's probably normal, he doesn't mind though. So please and body?