Pregnant? Or no?

I am on day 42 of my cycle My ovulation was August 3 checked with test Spotted for 3 days at the time I was supposed to start my period Have taken tests but they are negative (waiting until next week and taking another) I would be 6 weeks pregnant but still not testing positive? I called doctor & they said possibly implantation bleeding but they aren’t sure but weren’t concerned about any health problems. Anyone have anything to help ease my mind with this? Could I be pregnant and not testing positive? Anyone had implantation bleeding 3 weeks after ovulation? I’m driving myself insane with wonder and just waiting for a positive test so bad We’ve been trying since December