Faint positive v evap

I’m still too early to be testing but I’m a gluten for punishment. Took a test thought I could see something but it was so extremely faint I put it down to line eyes or a shadow and got on with my morning. I’ve just went to throw the test out and there’s a very definitive but still faint line there, it has some colour to it and appears to be getting darker which is making me question if it’s an evap line. I know reading results outside the time window are not reliable I’m just asking if anyone has had similar circumstances and been positive