What Causes Vaginal Bleeding While On Duphaston?

Hi, I have PCOS and trying to conceive. I am on day 4 out of 10 (as recommended) of taking Duphaston and I have some bleeding today, cramps as well although not painfull. My bleeding is something in between soptting and a real period. Is this day 1 of my cycle? Do I wait and continue with Duphaston at least tomorrow to see how it goes? Counting days and understanding what counts as a period is much more difficult than what it sounds. Thank you for your help!