I was recently due for my last shot and instead of getting it my Dr suggested I try the IUD. Since I had had 3 shots (with no period for 10 months) it was a very painful attempt and I did not get the IUD. Now I am 2-3 weeks overdue for a shot and have had unprotected sex. I was wondering when a period would return and if I am at risk for pregnancy. I was spotting a brownish discharge and now it is mucousy, also I keep having a bit of abdominal cramping... very slight cramping though. Could I be pregnant?

It all depends on your body, every woman is different. For some women (like me) it could take as little as a month for the shot to wear off, and for others, it could take up to a year to 2 years.

Yes, you are at risk for pregnancy. Even while taking birth control regularly, you are always at risk for pregnancy. No birth control is 100% effective.

A brownish discharge usually means old blood. Is it a really deep, dark brown? Your body might be finally trying to have a period, which would account for the cramping :)