I am 30yrs old and just gave birth to my fourth child in aug 2012. I decided to go on depo after having my baby. i have been on and off depo since i was 18. Four years ago when i was on it i never ever had my period. now that im on it again present day. this is my second injection i rexently got my period it is now going on a total of 16 days and i dont know whats wrong? Help!!!!!