different tests giving different results?

hi ladies, i’ve tested with pregmate and have been getting faint positives (i’m 2 days before AF is due) but i got a “not pregnant” on a clear blue digital this AM. Now i’m so confused and think we may not be actually pregnant. I’ve also had some light brown spotting and cramping yesterday which may or may not be my upcoming period though i’ve heard it could be implantation bleeding... sigh

anyway, is it possible to get a negative on the digital if it’s too early? I don’t know where to put my head other than to wait another day or two to hopefully get a positive on a digital.