PCOS and ovulation kits

Fiona
Hey everyone! I'm still pretty new to the community of glow.
I will give you a little background. My name is Fiona and I have been ttc for 5 and a half years. I found out two and a half years ago I have pcos. I have had really irregular periods up until a year and a half ago and I have now started to use opk's (as an infertility nurse once told me that there is no point using them when I didn't have a regular cycle.) I am now on a regular cycle and AF is due in the 22nd. 
How accurate are opk's with pcos? As just out of curiosity I took a test today to see what happens when I'm not in my fertile window and it came back positive as it was really dark. Are false positives common? I'm deffo not ovulating as I have no symptoms of ovulation but we will be dtd just I case! 
As I said I'm new to opk's and I just need some advice. 
Cheers :)