I'm on the depo shot I have had three shots total. My last day of effectiveness was yesterday had unprotected sex with my husband and he ejaculated inside of me the day before yesterday today I went in for my third shot have been feeling some cramping since yesterday and today I had a small amount of discharge reddish almost brown enough to wipe off and then it was gone. What could this be? P.S I haven't had a menstrual period in a long time so I can't rely on that if possible pregnancy.