I just ended my period about a week ago. I got the Depo-Provera injection about 4-5 days after my period had ended. My doctor told me that I just had to wait 48 hours for the injection to take full effect. However, I am hearing differently online, suggesting at least 1-2 weeks for it to grant full protection, some even suggesting months. When will the shot become effective? Do I only need to wait 2 days before it becomes effective AND as my ONLY form of birth control, or will it be weeks before it will work? This is also the first time I have ever used any form of birth control, especially Depo-Provera.