Femara and OPK

I took 2.5 mg Femara days 5-9 this cycle after a Provera induced period. CD 10 I started taking ovulation tests. A cheap brand looked similar colors on my very first time testing so I went and purchased the Clearblue Advanced Digital OPK. I got a negative that night but every morning since CD 11 I have got high fertility reading and now CD 22. Wondering at what point do I stop trying and call the doctor to start the process all over? Or keep going as it might still be coming?