Talk to Gynecologist on Cyst In Ovary And Irregular Periods

Hey, My age is 19 and my problem is irregular periods and a small cyst in the ovary. My periods were not regular since the beginning(I was getting it 6-7 days late almost every month) I was in Pakistan and started taking medicine for the delay in my menstrual cycle on the 23rd of Feb as I was getting married on 2nd March 2020. I took medicine (primolut n) for 10 days (day and night). When I stopped taking medicine on 3rd March, I had my periods on the 7th of March. I shifted to abroad and didn't see any stain in April. Then I got my periods on the 2nd of May. It was the last time I saw them until now(21st July 2020). I consulted a doctor and had my ultrasound test. She said that I have a small cyst in my ovary (about 3mm). She preferred me to take medicine (Duphaston 10mg) for 5 days(day and night). I want to ask the doctors of this group as the medical here is not too good. Doctors, please tell me, Am I having the right medicine? Is it serious for which I should be worried about?