This same issue has been driving me crazy too. Yesterday I bought the tests with seven in a pack and took one of them and one of the Twenty in a pack (the cheaper one is still positive the other one the line is not equal or darker) I don't know which tests your using but I would suggest a different brand and of course telling your Doc whats going on! Good Luck!
Are you reading them correctly? Both lines have to be equally dark. If one is lighter, it is not positive. If they are equally as dark, it could be a couple of things. One is that you are pregnant. Another possibility is PCOS. And yet another is a problem with Lh. Let me know if I can be of any help. Welcome to the forum :)
It will be positive like that after an HCG shot, did you have a trigger shot?