Ovulation tests getting lighter

I should ovulate 7th-8th according to my usual cycle. Glow thought I would ovulate on the 3rd. I have been using opks since the 1st and the lines started to show up, but very faint. Usually they get darker, today's test was lighter than yesterday. Eventually I don't even get a positive opk.

This seems to happen every other month. One month I will get positive opks and the next it never shows. I'm so tired of testing and getting disappointed; even from the opks. We have been TTC for 10 months. Has anyone else experienced the opks never getting positive or getting lighter? I feel like there's something wrong with me and I'm scared.

I'm supposed to ovulate in a day or two and these are the faint lines I'm getting. 😩