Faint line maybe?!

I have used the tesco's digital pregnancy test. Quite a long post (I apologise), but I'm just confused. When you use the digital tests u put a pee stick in to the digital monitor. I done a test on Friday morning & the digital reading said not pregnant. Anyway, I was emptying my bin this morning & thought I'd just have a quick look & it's come up with an extremely faint line. Is this normal for a digital or is there a possibility i'm pregnant? I have just done another one, so just waiting to see what that one says!