depo provera and pregnancy

i have been on the depo shot since june 24 and before that i was on femcon, anyways since august 11 i started spotting brown discharge, then on the 13th i started to have cramping and regular spotting, i have been spotting on and off since the 13th along with cramping, i have had bad heartburn, nausua and vomitting, increased sex drive, cravings for weird food, sore breats, bloating and swelling, and serious fatigue ( like as soon as i wake up i feel like i need to go back to sleep) could someone please give me some advice on what is going on... thanks