Ladies who have experience with first response

We have been trying to conceive for almost two years now with one misscarriage last July and no sticky ones since. My period is due anywhere from the 2-5th I took a first response today that says 6 days before your period thinking if it was 2-3 I'd get lucky. Well there was a line before the 3 minutes was up, and it's still there now but it's not pink. It's like an evap line except it happened immediately. So for people who have used these tests before I'm just curious if you've seen the line too and ended up being pregnant or if it's just always there and would be pink if I was. Thank you :-) (I'm going to test again Saturday morning)