Fading OPK

CD 22 today, and after getting a + opk yesterday, today the line is still there but it's fading...which is normal...the luteinizing hormone surge is now over, but there are still remnants of it in my system, which is why it's being detected by the opk.

But now I'm confused when I compare the opk results with my chart - there was no O dip around the time when the opk said that I should have O'd - I was always under the impression that I had an O dip on day of O...or around there anyway...either way I usually always had a clear temp dip around time of O - which there wasn't one this time:

The program set my day of possible ovulation on CD 22 with the blue line, which it automatically put there because of the +opk I filled in for yesterday.  The only dip near to day of O is CD20 (day before +opk), but it's not any lower than previous dips that cycle, and usually it's pretty noticably lower, even if only by a little bit.  However, my temps have been lower this cycle compared to previous charts - I think it may have something to do with the weather becoming cooler.  SO, the thing to do now is to do opk's next cycle as well and compare the 2 cycle charts and opk readings...maybe I've been O'ing 2 days after the dip all along...

There was still no ferning today either...that's just weird.  I think I'll take another opk tomorrow, just to see what it says and whether it's fading even further.