I AM SO CONFUSED

Ma

What are the chances of getting PG if you miss your second DEPO shot? Can you get pregnant in between the window that your next shot is due?????? I only had one shot but my period came regularly. I missed my last shot due Feb. 2 and my period is 16 days late. Does your period go away by the 3rd month if it was regular??? Has anyone ever gotten pregnant 4 months after their last shot??? Is that normal? Or common???