Answer:
If you want to stop the injection all you need to do is not have your next injection. Your periods and natural fertility may take a while to return after you stop using the injection. However, it is possible to get pregnant before you have seen your first period. If you don't wish to become pregnant then you should use another method of contraception from the day your injection is due. If you have sex without using another method of contraception you may want to consider using emergency contraception. It takes 3 months (12/13 weeks) although it would take anywhere up to a year for your periods to start again.