Have you had no period since your delivery? If you have had periods, when was the last one in relationship to the injection?
Which contraception injection did you start 2 months ago? Thank you.
It sounds like you got the depo injection about 1 month after your last period. That would explain the heavy bleeding. The depo shot is best given just during a period, when the uterine lining is thin.
When your last period was a month ago, your uterine lining is likely thick, and that is what is causing the heavy bleeding. If so, there is not much to do except hope the bleeding resolve soon.
In the future, if you start the depo shot, do it during a period.
If the bleeding continues and is a problem, a D&C might be needed. Best wishes.