Possible miscarriage?

I’m 7 weeks pregnant today. I know I shouldn’t trust HCG pregnancy tests to determine if my HCG is doubling or not. I know it doesn’t do that but I’m freaking out because my test is lighter. (First was a week and a half ago, and second is today). I also had some brown discharge when I wipe, yesterday and just very very dull cramping. Is this a sign that I’m slowly miscarrying? Shouldn’t my test at least be dark as the first one? I’ve had two miscarriages before and I can’t help but worry that this is my third miscarriage. I feel helpless.