Should I keep taking Multivitamins for irregular periods?

Hi doctor,

I have been having irregular periods since I started getting period from age of 13. Bit history about me is that in my childhood I used to be sick with cold and cough a lot of time and my weight was always less. After I started getting periods, they were irregular. So, I consulted a gynecologist and she gave me some Multivitamins and they became normal. When I stopped taking them, they again became irregular. At the age of 18, I consulted another gynecologist and he said I have a cyst in one of my ovaries, so, he gave me a medicine to dissolve the cyst. My stomach was very painful at that time. Then, after that again the periods became normal and again after some time, they became irregular. So, when I consulted another gynecologist, she gave contraception pills. They were normal until I was taking them. Now, I have stopped taking any medication from past two years and suddenly from past six months, my weight has gradually increased. My height is 5'2" and my weight is 130.07 Ibs. Recently had a scan done and the doctor says they have found a very minor cyst in both the ovaries. And he has suggested losing some weight. But even when I was underweight, I had the same issue. What shall I do? Shall I keep taking the Multivitamins until my meditating age and stop after that?