Clear blue OPK tests

So ladies - I have been taking clear blue digital ovulation tests and they are coming out negative (both glow and another app say I am in my fertile window which I know doesn't mean I have ovulated yet,) but when I remove the test strip there are two super blue lines. Does anyone know if that means anything? The first time I took it out (3 days ago) the control line was blue and the test line was very very faint. Everyday the test line gets a lot darker, but it's still digitally saying negative. Just curious if anyone knows anything about that. :-)