Pregnancy

Arianna

So I'm on the birth control shot and this is my 3rd month of my first shot. And I usually get my period on the 22nd of every month but the last 2 months I got my period every 2 weeks. But now july 22nd comes around and I don't get my period. It came on a little but it wasn't a full in flow yanno. Should I be worried about pregnancy or is it just my birth control?