Hey Welshgirl, as a LONG time user of Depo, I still can't give you many answers, but I'll try my best.

If it's only the one shot, it shouldn't take too long. Unfortunately I can't give you an "exact" timeframe like the pill, as it depends from person to person as to how quickly your body "breaks down" the drug and uses it, and body type, (it's stored in your fat, so if you're a little more "padded" like me it may take longer). It "shouldn't" take more than a month or two, but then again it's very subjective because of the above reasons, but I know in studies done that "most" women (and I say most to cover my butt, it honestly is a high percentage) return to normal fertility after a shot of it.

Geee whizz, I hope I haven't scared you to death ... I personally LOVE Depo, and think it's a great contraceptive choice ....