CD 15 still no positive opk

Hey ladies!!! I have a regular cycle and usually ovulate CD 11, CD 13 or CD15. I'm currently CD 15 and still dont have a positive opk? I had one that was close to positive at 12:30am this morning but not quite. I'm confused if I didnt ovulate or just keep testing and see if I get one late tonight or maybe tomorrow? Or maybe just track my cm? HELP!!! glow says I won't ovulate until Saturday, premom tells me today and ovia ends my window on Friday so I'm lost!! And they all have the same data. Thanks in advance!!!