Depo shot

Ive had 4 injections over the last year or so of depo provera. My period had stopped completely with only minor spotting. I have been off my shot for about two months now and ive already had two normal periods. Does this mean the depo is no longer in my system? Ive been having unprotected sex with my partner and he's cam inside me. Ive been very moody and hungry lately. A lot more then I'm use to. Could I b pregnant?