What is your experience with test strips being faint, but a clear positive on a FR test?

So I was able to order some pink dye test (I've

been using blue dye tests in my other posts). I

bought a FR test and Accumed test strips. I took

both test today with FMU, with the FR test you

can definitely tell it's positive, but I'm getting

faint lines on the Accumed test strips and the

lines do have some color. I've had a chemical

pregnancy in the past that is why I'm concerned

about it. I've also been having bad period-like

cramps and backaches for the past 3 days, but

only at night. I am 3 days on AF, I would think

that by now there shouldn't be any faint lines or

I am just stressing myself out? What is your

experience with test strips being faint, but a

clear positive on a FR test?