I have been bleeding since feb 28 and still spotting i got my shot on the 18. why i keep spotting on and off.

Probably normal.: I would guess the shot you had was depo-provera, the birth control injection you get once every three months. Irregular bleeding is, unfortunately, reasonably common after that injection. It may lessen with time. If it becomes a continuing problem, your gynecologist may sometimes suggest short-term estrogen medication that may help.