Those are still nice lines. Keep testing until the lines fade out. Normally after a surge it should be gone in two to three days, taking you to very light or absent second lines. If it doesn't get lighter and stays dark, you might not be able to trust the OPK's with your poly cyctic ovaries. The reason being... that FSH is always going to be in your system, bringing up cysts and what not. PCO is when you get cycst regularly but they haven't affected how thick the lining of your ovaries are, so the egg can still break through. PCOS is when the cysts happen SO MUCH that the lining of your ovaries over time thickens, causing difficulty for the egg to break through the lining of the ovary. That's my knowledge of it, anyway. You'll also want to be careful about taking things like Soy or Clomid, since your ovaries might be swollen from PCO. (This I know.. from experience.. had a cyst back in JANUARY and ovary is still swollen & being monitored from it)
If since you aren't charting, you don't get your period in about 16 days past ov, and no +hpt by 18 dpo, you might have an anovulatory or cycstic cycle.. where the egg isn't fully released, since your +opk was done on cd 8.. I had a pos on cd 10 this cycle and then again nearly pos on cd 17 of this cycle so I'm in the same boat as of now.
How was your CM when you got your +? if it was eggwhitey then you possibly DID in fact ovulate. Good luck!