Fluctuating ovulation tests normal?

Alex • 👩🏻-25 👨🏻- 29 👰🏻+🤵🏻2-16-14 🐶- Hank 🦊- Nahko 🐱- Whitey TTC 4 years. Anovulatory ansd PCOS (3) failed femera on 2.5/mg and 5/mg. First round of Clomid CD 5-9
Hello all. It is my first time trying to track ovulation while on letrozole. Started super light. Got a test that was about a shade lighter than control line. This made me happy ! Tested next day and line was super light. Next day back to being a little darker. Did I already ovulate and miss it? Is it normal for it to go back and forth so drastically? CM is also non existent. Is this most likely a failed round of treatment?