Have I ovulated yet??

[Mitty]

Ok so I've been using opk's for the past few months and always get a just pos cd 14 and/or cd 15. So this month I didn't get a pos till cd 18 and again cd 19. I had some cramping yest (cd19) so thought I o'd then. But today cd 20 I've just gotten a VERY pos opk! Cp still very high and open. So justwondering is it likely I haven't ovulated yet?? Getting slightly confused!