Need Help with Ovulation Strips

Ladies I need help. This is my first time using ovulation test strips. My app said this past week I was suppose to ovulate, but the test strips say if the test line isn't dark matching the control line it's NEGATIVE. So the past 5 days I've had a light line, but it never got as dark as the control line so I have marked them as negative in my glowapp. This morning I tested and there is absolutely no line. Should I just keep on tracking and hope for a dark line next month, or go back and Mark the darkest day as a POSITIVE?