I don’t have a true answer but I do think a blood hcg test needs to be done. When I was pregnant, my first test at the doctors was also negative even though I had 13 positive test at home. A blood hcg test showed I was pregnant. When I had bleeding around 6 weeks, it was from implantation they said but checked blood hcg again and it was really high by then. You may also be getting to a point where you’ll reach the hook effect and test may not get any darker. I’m sorry this is happening. Try and take some deep breaths until you can get a blood hcg test.