Period problems

So I've been on birth control for two years ever since I've gotten on it my period has stopped. I just recently got off of it due to doctors orders and having them like normal. I was supposed to have my period March 17,2017 I had it that day and that was it. I am sexually active but I've taken pregnancy tests and they all say negative. I do already have a little girl so I know if i was pregnant or not. I am also very stressed and depressed with losing my nephew recently I'm just nervous as if why I've only had it one day this has never happened before. Has this happened to any else before?