anal... warning TMI!

so girls this is super gross, but i was wondering if anyone else gets the runs after anal sex? Me and my fiancé tried this morning and apart from a little discomfort at the start it was was fine... until now, I have super bad diarrhoea and I can't think of anything else that could have caused it? Is this something that happens to others or just an unlucky coincidence? 😳😳😳