I completely agree with your Gynecologist's advice that you should loose weight. I also see that your menstrual cycles have been pretty irregular right from the beginning, so the approach should be to address the balancing of hormones in your condition. In such situations, I would like to advice you with a combination of therapies along with your Gynecologist's prescription. They can be Yoga
therapy, Personalized diet plan
based on your constitution (based on Ayurvedic concepts) and Acupuncture
treatment which will help you to large extent of addressing your problem.
You may approach and qualified Yoga therapist, Dietician and a Acupuncturist in your location.