one positive then negative next day

I took a pregnancy test yesterday and it was positive within seconds, although super super faint. It was definitely positive and not an evap line though! I took a digital today just because I'm the type that needs to see it in writing to be sure and it said "not pregnant." I'm bummed. AF isn't due until tomorrow and my cycle typically starts a day or two after it says here on the calendar so i technically could be a few days out. Is it possible the digital was just too early to test? How soon should i take another, or should I just take another pink dye test?