Prolonged periods. What should i do?

I am a 38 year old lady and I have pcod due to which I have irregular periods . Sometimes I get periods after 3 months and usually after 45 to 60 days . My usual days of flow is till 5th day . This time I got my periods after a couple of months and as usual my flow reduced from 3rd day and 5 th day was minimum. In my 6 th day i again started getting period flow like how I get in 3rd day and it is lasting till 7th day. Sicne past 1 month I am doing dance practice once every week. Is this the reason of this prolonged periods. I am very very worried because I never had periods till 7th day. What should I do ? I have read in Google that it might be due to ovarian cancer and since then I am not able to focus on anything. Pls advice if I should consult a doctor right away.