Wondfo strips false negative?

[Nodrama]

Has anyone ever had these not work? I used CVS ones along side and got a positive around CD12 but I don't usually O until CD17 or so. I've had 3 fairly regular cycles since stopping BCP. Still all negative on the Wondfo though, not even remotely positive. I've had consistent EWCM at the right time the last 3 months but this month nothing! Ugh, this is all getting so frustrating.

 

[Mrs. Atole]

Has anyone ever had these not work? I used CVS ones along side and got a positive around CD12 but I don't usually O until CD17 or so. I've had 3 fairly regular cycles since stopping BCP. Still all negative on the Wondfo though, not even remotely positive. I've had consistent EWCM at the right time the last 3 months but this month nothing! Ugh, this is all getting so frustrating.

I'm surprised to hear this as wondfo is my go to brand.