Whatcha think?

I've been off of birth control (depo/pills) for almost a year and have been tracking my cycle religiously. My fiancé is never home when I ovulate due to working in the oilfield, but he just so happened to be home this past month due to a schedule change! Wellll i took a test yesterday morning and got what i thought was a faint positive result, took another test and it was clearly negative! My period is 4 days late.