How faint of the line should it be? :)

Hi,

Two days ago I had severe cramps and my bbt was around 98.76 so, went to the doctor (6days before my period). I was wondering if I was pregnant. Of course checking that early, they said its negative.

Today (4days before period) I used First Response 6 day early pregnancy test and I see a faint line. But not sure. How faint of a line should it be to find out I’m pregnant? Please let me know, I’m going crazy :)