Well considering it's the type of birth control you have decided to use, it might be a good idea for you to brush up on the info. I personally have no idea......I've never taken the depot. But in my opinion, if you've had unprotected sex, it's possible. I'm pregnant and was on the pill......so go figure. The best advice I can give you is relax and wait it out. Nobody can tell you if you are or if you arent, but I will say that if you are, it must be a pretty special baby to be created under such unlikely odds! That's the way I keep looking at mine.
Good luck to you and I hope everything turns out the way you want it to.