Well ive been on Depo for about 1.6 years. I was suppose to get my shot in Feb 14 2008 and i didnt but on Jan 19th i had sex and didnt use any pertection. Now ive been spotting alot. i havent had a period since ive been on depo  ivebeen late a couple times and got a full period. But this time is different im just spottin andmy nipples were sore(very painful ive never had a pain like that) for a couple of days, they even hurt in the shower.. Then the pain has went away but now my nipples have gotten darker.but  in a couple of days they went back to normal............. Could i be pregnant or could it be just a side affect from depo??? Please Help