hmmm that only takes me to the same thing and details of you on another page not actually your chart.
it could be that your body is gearing up to O. what type of opk do you use? how many times a day?
with dip test opks it could be easy to miss if only testing once a day which is why i always temped as well because then i had a better idea. i get O pains and change in cm a couple of days before i Od so it could be that or maybe dtd a bit different has knocked your cervix.
i hope you do O soon and get a great new year gift in the shape of a bfp