Frer lines

So frer lines get super dark? At what HCG are they wayyy darker than the control line? I’m 6 weeks and took a test Monday and today and they seem to be the exact same. I would have thought the test line would be even lighter. It’s worrying me a bit so what’s everyone’s experience with this? My lines have consistently gotten darker up until this week so it concerns me a bit. Top pic Monday and bottom pic today.