if you take the pill on a regular basess then dont worried to much but you still have that one percent
You're on birth control, and you had sex three days before you're period ended? Is that correct? I'd say the chances of you being pregnant are very slim. Go to the doctor if you don't believe the home test. Oh, and if you're worried about becoming pregnant use condoms along with your birth control.
Everyone is different but if you really want to be sure just get your blood tested...