Have I missed ovulation?

These are ovulation tests I have taken over the last 3 days. Last night I got the darkest, but didn't it's not the darkest I've had in the past months of testing. I assumed I would get a darker line today and I could get a donation last night. Now the tests today are lighter than last night. Fluctuating between low and high fertility. Has this happened to anyone else and is it possible I have missed my window to inseminate?