No Period for Over a Month Now
According to Planned Parenthood, women who use emergency contraception such as Plan B, may have irregular periods afterwards due to increased hormones in the body and/or due to hormonal imbalance which can cause a delay in menstruation from a few days up to two-three months. It can also cause the flow of your period to be either lighter or heavier than normal. As you know PCOS can also cause you to have irregular periods.
There seem to be multiple underlying reasons that your period could be irregular including PCOS, taking emergency contraception, and taking an unknown pill given by your Gynecologist. As you did not mention how old you are, whether you were having regular periods prior to this event, or whether you have ever had periods of irregular periods so it's hard to comment directly on what exactly is going on. It is best if you make an appointment to see your gynecologist, primary medical physician or an adolescent medicine specialist. If you don't have a primary care physician and you live in Northern New Jersey, you can call the Adolescent/Young Adult Center for Health at 973-971-5199 for an appointment with an adolescent medicine specialist or contact your local teen health center or Planned Parenthood.