Ovulation test confusion

Hi all. I bought the ovulation tests from target. They have a control window and a test window. The directions said the line in the test window should be darker than the control line when ovulation is happening. But it never was. But I kept testing and by the end there was barely a line there in the test window. So did I miss my ovulation because I was looking for a darker line when there really just needed to be a line present? I'm new the the ovulation testing. Thanks!