Hi I Give Birth To My Son 13 Weeks Ago

Hi I give birth to my son 13 weeks ago and since giving birth I've been bleeding for the past few weeks with brown discharges every day not a lot maybe a large table spoon full through the day and same again at night and it hasn't let up at all. I got the contraceptive injection 3 weeks after birth and don't know if this may be contributing to the brown bleeding my sex life is nonexistent because of this and it makes me feel self conscious having to wear a pad everyday I really don't know what to do.