Ovulation test.....

So I decided to try doing the ov test this month because my app told me I was ov for like a week straight.... iv done one a day for the last 4 days and the lines keep getting fainter and fainter. If u ate ov ur suppose to get two very dark lines, the first day I did it I got one dark line and one faint one. This morningI could barely see the second line..... I'm confused did I miss my window again?