Can Regestrone Cause Brown And Yellow Discharge Instead Of A Full Period In Someone With PCOD?

I have sex with my boyfriend on march 13 and my last period where on feb 19 to 23 my average period cycle were 35 days and i didn t go through my period on march so, i do pregnancy laboratory test on march 30 and other urine tests all shows negative result.And i have pcod too....so, i consult my doctor she gave me regestrone tablet and prescribed me to take it for 5 days thrice a day and after stopping the tablet i have a coffe brown discharge which lasts only for 2 days after that i have a pale yellow discharge what does this means day before coffee brown discharge i even go through urine that also shows negative then when did my periods arrive....what was the cause can anyone plzz explain....plzz