What's up with my opk?

This is the first month I've ever used an opk before. My periods are irregular after coming off birth control, and I finally got my period from February 4-9. After that I decided to start tracking. I went from having virtually no cm or second line on Feb 10, to having watery cm start by feb 13 and a light second line. By Feb 18 I woke up to egg white cm and the darkest line I've gotten yet, but by today my cm has become back watery and creamy as well, no signs of the egg white cm anymore. Plus my lines for today got significantly lighter as well. My bbt also went up a whole degree too. My question is what's going on? Did I surge already even though my tests never showed a positive surge? Or am I still in my fertile window?