OPKs 2x a day, but is it possible I missed my window somehow?

jea

I’ve been doing the strips twice a day, but nothing ever got quite as dark as the control line. Today the line started to get really light again, so not sure if I missed it or I just didn’t ovulate this month? Any ideas? So frustrating!

Average cycle: 26 days

OPK Results:

CD 7-9: Medium

CD 10-11: Light

CD 12-13: No line at all

CD 14-15: Medium

CD 16: Dark (But not as dark as the control)

CD 17: Light again (Today)