So last period was jan 31- feb 5. Since I've stopped bfing in sept 2014 my periods hae been ever 40days. So 40days of this cycle would have been march 10. Well now I'm at the end of day 42 about to be 43. I too a test march 10 with a dollar general brand and it was bfn. Every time I update glow my dates of ovulation chane so I realize that I prob ovulated later? I really want to know but man I've took 5-6tests already throughout the last two weeks . Should iget a different brand,l and test or just wait it out?!  ( next time if there is a next time, I really hope not but I'll def get opk's !) Thank u !!