These tests will always show a faint second line. They arent good for early testing... As the sensitivity is higher than most hpts. Try a frer. It has the lowest sensitivity and can pickup 6 days before period is due and pink dye is far more trustworthy than blue. Good luck !!
Blue dye tests are satan in a Sunday hat, they are notorious for giving what looks like positives, but are actually evaps. I suggest testing with a pink dye test, the only time I trust these is when it's dark, otherwise, I know too many who've been mislead by this test. Good luck!