your doctor didnt explain that you could spot or bleed for up to a year on the depo. so it's normal to do so on that kind of birth control.
i was on the depo and i was spotting for 1 1/2 months. i decided not to get the shot again and im on birth control pills. which stopped the bleeding in four days. i have cyst and it's good to be on birth control for that reason.
so i cant tell you, nor can your doctor tell you when you will stop bleeding.
my girlfriend bleed for six months and she gained a lot of weight so she got off of it. it's hard when your in a relationship and you cant have sex.
so your period might stop with the second shot or it can continue.
you should research about depo shot on the internet. you should think long and hard about whether you want to stay on it or not.
good luck