Hello, Im 20 Years Old. I Started Mensuration At The

Hello, Im 20 years old. I started mensuration at the age of 12. It was very irregular at the beginning like very few months. Then it became very irregular and now I don't get my period. One of the doctors I went to told me I have PCOD. they put me on a treatment of Primolut N for 10 days every month for 6 months and i got period just after a few days after every 10 day of medication. But as soon as the medication stops I go back to not getting period. My physician suggested that I continue this primout treatment for longer as it didn't have any side effects. However a gynecologist told me to start on metformin. I am 154 cm and 53 Kgs, therefore my physician said that metformin isn't of much use. Can I have your suggestion on what to do?