Birth control


I have a pretty normal cycle. My period is hardly ever heavy and is normally 4 to 5 days long. After 3 years of being off birth control I began taking them again. My doctor said to start it the first day of my period, which I did. I bled very light and Since then I haven't bled again. Also, I normally start on or a few days after this app predicts but this month I started 3 or 4 days before. Any one have a little insight? Or personal experience? I'd like to believe it is because I started the birth control again.

I'd also like to note I've used this birth control brand for five years before and my cycle ect was always consistent.