What's the different between pink fainted line and evaporate line?

I took a pregnancy test last night but my light was dim so I could really see the fainted line so I toss it in the trash but when I woke up this morning and decided to take a peek at it again and I notice a light pink fainted line on it and then k decided to take a digital clear blue but it said I wasn't pregnant and I couldn't take it so I call my doctor told her about it and she ask me to go in for a blood work because I've been having pregnancy symptoms for almost two weeks now but I'm not due for my period tomorrow!! So confuse