I've been having dark brown discharge for about 2 weeks now. this started after i had unprotected sex. but i am on the depo-provera shot. what could this mean?

Prob from Depo: You should check a pg test- probably will be neg, it is not uncommon to have spotting from the depo, and it is most common with the first shot, if it continues your obgyn can give you some low dose hormones or other meds to try to stop it as well as do an ultrasound to make sure nothing is wrong with the uterus that is what I do with my patients.