Um what?

I just had AF (literally ended 4 days ago). Idk why but I had the urge to take a test knowing it would come out negative (idk why don’t judge me lmao) but anyway a faint line showed up and ??? has anybody had this happen before?? The line has colour to it so I’m confused as hell (I know it is very faint and hard to see, I apologize, cameras don’t do these things justice).