If u were getting ur shots regular and on time there is no way you could become pregnant. I have been on the shot for 7 years and never had a problem. When I got tired of the shot and got off and had sex with my partner I became pregnant but not right off. It took about 4 months for all the medicine to exit my blood. But however there is a 1% rate that out of 99.9% only one person could actually get pregnant and that is due to your body not accepting that form of birth control, your body fights against it and not with it. And really if its something that god wants to allow to happen no form of birth controll will help, if god want to bless you with a life. :)