So I had my first shot almost three weeks ago. The doctor told me that I will probably have unusual bleeding but then in about 6 months I won't have my period anymore. Well I was suppose to start my period 4 days ago and I have not had any bleeding what so ever since I got the shot... Could it already be working? Is this normal? I am sexually active but we always use a condom and are very responsible with it. Could I possibly be pregnant? Has anyone else experienced this? HELP!