Early ovulation with Femara/Letrozole

So I’m on my very first round of Femara, and I did 5mg days 3-7.

Usually I ovulate around cd 17/18 and usually my OPKs will get steadily darker before I O.

This month my husband and I have been having sex every other day since cd 10 (maybe 11, I didn’t keep track).

I took one opk at cd 11 and it was really light (as expected). But then two days later I got a really dark second line and I wasn’t sure if it was darker than the control but I thought it was too early so I didn’t pay much attention.

Anyway, I’ve been doing daily OPKs since then and they are getting lighter. Today’s was really faint. I’m supposed to ovulate in 3 days but could I have missed it??

I’m going to keep testing daily but I’m worried that we only had sex like once or twice before I ovulated. I thought we’d have more time. Has anyone else has weird OPKs while taking Femara?

Has anyone else ovulated like a week early on Femara?

Any insights/advice is appreciated!