I have never been on the shot, but I will tell you that any time you change birth control, stop using birth control or start using birth control, it's going to mess with your period. I thought the effects of the shot lasted about three months.. Maybe I just think I read that somewhere... Like I said, i've never been on it.

But, if you're having sex, there's always a possibility of being pregnant. In your case, with the info you've given, i'd venture a guess that you're not. You're probably also stressing about it, which is making it worse. If you're that concerned, take a test.

It can be a side effect of the shot. But if you have been having unprotected sex, you are also at risk of pregnancy.

There are so many side affects of that damn shot it probably is one of them.It does mess with your system after you get off of it and it takes up to a year to get preggy so I doubt it.(i have done some research cause I just got on it about a moth ago : ( )