HUGE QUESTION !

I’ve been getting faint positives for the past 4-5 days ... it’s early on , I haven’t even missed my period yet ! HOWEVER, I had a miscarriage a couple months back because I’m rh negative and i had no clue .

I want to get my rho-gram shot soon but I want my line to be dark enough for my doctor to see...

How long did it take for you guys to get an obvious second line ?