Birth control bleeding

I am 4 months postpartum. After having my baby my bleeding stopped at about 4 weeks after labor. I got on birth control after my 6 week appointment and every since I got my birth control I’ve been bleeding non stop for the past 3 months. Any other moms dealing with this ? If so did your bleeding ever stop ? I decided not to go back for my second shot hoping it will stop on it own. My next shot is due between this week and next week