Disappearing line!? Help, please!!

Chelsea • Boy mom of 2 💙
So, I tested with a blue dye yesterday and I saw a second line and then I couldn't really see anything, but I can see a line on it today but I'm sure it's an Evap. :/ Soo. Today I tested with a first response and I watched the strip soak up the pee lol saw a very faint line that had color but after a couple seconds it went away? Any suggestions! Thank you!! :)