I don't think you could be preg. Depo is very very affective, but if u do want to get preg then u should get off depo cause it messes u up. I was on depo for a year and a couple of months and I didn't get my period at all and now I. Off depo ad still haven't gotten my period. Me and my boy friend are TTC but I don't think I can cause I haven't had a period. So if ur planning kids in the future should get off depo and use a diff kind of birth control
the depo is effetcive as soon as you have it, it takes effect immediately
Ideally with any new contraceptive you should use other methods (condoms) for the first 14 days. It is possible to become pregnant. You need to wait a few weeks then do a home pregnancy test.