Can Diane 35 Be Taken For PCOS And Irregular Periods While Having Light Brown Discharge?

few days back i went to gyno dr in hospital.i have pcos and irregular periods.she advised me to take diane 35 on 1st day of cycle.today is my due date and im having very lighy brown discharge after 5-6 hours since last night.i have taken pregnancy test today in the morning it was negative. Now please help me that shoulf i start diane today or not? What if im pregnant or what if this is not thr start of cycle