Talk to Gynecologist on Possible PCOS Diagnosis - Confused

I have had irregular periods for a while now, and I sometimes got ovarian cysts which went away after I took medicine to get my period. This year I failed to get my periods until I took medication after I didn't get them for 3 months (I was told to by my doctor) and I didn't get periods naturally.

My doctor did an ultrasound the third time this happened in a row and said that it looked like PCOS. She said that my weight was fine - although I could do with gaining a bit more - so she wouldn't tell me to make any lifestyle changes. But I should take medicine to get my period if it didn't occur after 3 months.

I've heard that it's not healthy to keep taking medication because it causes fertility issues later. Is that true? Would it affect my chances of getting pregnant in the future if I wanted to? Also, everyone with PCOS says they made diet and lifestyle changes so I'm wondering if I should be doing anything or of there are things I should avoid.

Also, I got 2 periods natural