I have been on the depo shot for 9 months, however the most recent time, I was overdue by a week before I went in and got the shot. That day I had unprotected sex with my boyfriend. It's been three weeks and now I'm spotting, as well as experiencing PMS symptoms, which has never happened o me while on the shot. I don't know much about these things, but what are the chances that I might be pregnant and is it even possible?