I will give you some information that will explain everything so that you finally know what exactly is going on.
Depo and the mirena iud both have the same type of hormones. I have used the mirena iud...I am giving you this story for comparison.
So, there are 3 things that depo can do.. Many women say "oh yeah, I never ever have a period with depo!" some women say "well I did not noice any chnage at all, sure wish my period would go away.
Women like you and I react differently to the hormone.. It causes us to bleed every single day.
The hormone causes your uterine lining to thin out, which causes many women to lose their periods. For some women, it become so thin that it is like an open wound, they basically bleed everyday.
This is what is happening. Depo may not be the best method for you.. :/