Odor from rectum. Caught something from girlfriend?

Patient: Had sex with my girlfriend. Her vaginal odor this particular day was extremely terrible. A pungent-fishy odor, but extreme! I notice about a day later I have the same odor now pertruding from my rectum! This was three weeks ago and we haven’t had sex since. The odor is there most of the time but than goes away for a day or two. Please help! It’s foul. I have NEVER had this odor before that day.