Missed period on Depo??

Has anyone missed a month of there period after going off the Depo shot? I recently went off the Depo in April and I've had my period every month since then. The first 2 months they came at the same time at the beginning of the month but then became irregular and came at the end of the mouth the past few months. But it still has not came for the month of September.. I don't wanna take a pregnancy test and it be negative and get upset again. So if I don't get it by next weekend I'm gonna test. But I was just curious if this has happened to anyone else!??