Skipped period, when to start OPK???

Lauren • Mama, wife, Christian. Diagnosed w pcos 8/2018. 👧👼🏻👼🏻👼🏻👦👧👼🏻🤰🏼

So AF was due the 20th and never showed so I am now 3 days late. I have spent soooi much money on tests and they have either been squinters or just stark white BFN, so I'm kind of just over this month. :( since I have now skipped my period, when do I start opk? Do I wait for AF? I don't want to waste an entire cycle but I also do t want to waste these opk tests. Thoughts???