What Causes Prolonged Menstrual Bleeding After Starting Rigevidon?

hi, i have started taking the rigevidon a week ago on the first day of my period as adviced by my doctor. i would normaly have bleeding around four or five days, but i am still experiencing bleeding now which got me worried. i am not able to see my doctor as i am abroad for a few weeks. should i stop taking the pill or is that normal? thanks