Irregularity in Periods. 27th april.

I am 22, I have PCOD since my periods started (at the age of 12). I have had periods for 1.5 months when I was 12 but then my gynae recommended me to eat Dafflon and said my hormonal treatment will start as soon as I will reach at the age of 18. Since then I have had irregular periods, and the average days for my periods to last is 10-12 days. After, I crossed 18 I was given Diane-35 for 3 months after which irregularity was not there. But when I stopped taking the pill after 3 months, soon after I again started having irregular periods. Since then till now I am on and off on Diane-35 and irregularity continues as soon as I stop eating my pills after the desired duration. I have had sex also at the age of 21 after which is was somewhat regular but just after 1 year the irregularity has again started. Recently, I was on Diane-35 for 4 months. Then after stopping I had my period on 17th April till 22 April which is a normal duration but I have started it again from 27th April.