I'm soo confused!!!

Today I did my ovulation test it showing 1 line darker than the other... but yesterday when I test it showed both lines where the same... Base on this <a href="https://play.google.com/store/apps/details?id=com.glow.android">glow app</a> I ovulate on Monday and my other app say I ovulate Today...Can someone please explain this to me or have experienced this. Also the last test is from yesterday.....