Positive OPK question

Jen • 40 years old. PCOS. Daughter born 5/25/17 after beating infertility! 💜 Daughter #2 born 3/21/2019. 🎉
Hi! 
So, I had a very positive OPK (test line darker than control) on March 1. 
I'm due for AF on March 17 (2 days). 
Yesterday, I had another very positive OPK. 
I guess I didn't end up ovulating with that first positive OPK and instead I am now? 
I took a FRER today (13 dpo, if I did ovulate that first time) but got a BFN
Any thoughts? Thanks for your time!