What Causes Delayed Periods While On Althea For Treatment Of PCOS?

Hi doc, .. a week before my period i had a heavy period that last 8 days.. i went to doctor to let it check. We did a trans vaginal ultrasound, found out that i have pcos. There are more than 12 small follicles in the left ovary. She adviced me to take althea immediately since i still have period, though its not the first day. While on the 5th day of althea i have unprotected sex with my partner. I just finish the whole tab, and im already in 5th day of the 7 pill free.. and still no period yet.. im worried.. please advice. Thanks