Hello Doc , I Took The 3 Month Depovera Shot

Hello doc , I took the 3 month depovera shot for the first time April 2015 , missed it in July , and had it again in September. Only twice I've had the shot. I started seeing my cycle in March of 2015 for the first time since July 2015. My periods have been 14-20 plus days ever since. Are you able to tell me when does the depo shot exit the system and how can my hormones become balanced once again. I want to have a baby now and I feel as if I can't.