Almost the same thing happened to me!!! My period was just about over and I guess I put in a tampon and forgot about it. It ended around the saturday of memorial day weekend and its now a week later and I had been having really bad bladder leaks and cramps and an awful smell. one day i was going to the bathroom and felt a little pressure down there and realized i had a tampon coming out!! No blood on it, so I guess my period was mostly over when I put it in. I had been having less discharge than normal, but with an awful awful smell and Im guessing the tampon was the culprit!