HPT dye color as help

Katy
I am 8 days past when AF was supposed to come. My periods are always on time. Even after my Miscarriage I got right back on track. The only time I have been this late was when I got Preg (and miscarried) I took a first response the day AF was supposed to show. It was pink dye and a BFN. I have take 3 Dollar Store test with pink dye and they are also BFN. 
Is there really a difference between the pink dye and the blue? I was have preggo symptoms at first. Nausea, sensitivity to smell,sore breasts. But now just the sore breast and light cramping. I'm pretty sure AF will show herself soon but do any of you think there is a chance the pink dye tests were wrong? Only one was taken in the morning.