prolonged, heavier period after starting the pill

I recently started taking the pill and my period hasn't stopped or slowed down. I started taking the pill on the second day of my period because that's when I had my doctors appointment and got my prescription. The doctor said it was fine to start taking it straight away but 8 days after starting my period I'm still bleeding and it's not showing signs of slowing down. Anyone else experience this when they started taking the pill?