Metformin / + opk but no AF 21dpo - hpt

I have been taken metformin fpr about a month and and got a positive opk about 3 weeks ago but sill no AF so must of been a false positive! I have ridiculously sore boobs though tingly at first and now dull and achey for atleast 2 weeks but at 21dpo no + hpt or AF.

Whats max LP that pcos suffers have experienced after a positive opk?