Implantation and when to test

So I am nineteen days late today. I started spotting on the fifteenth day thinking AF was coming. But nope the spotting stopped. So I'm thinking maybe that could have been implantation bleeding. So I went on Google to see how early can u get a positive after implantation bleeding and it said six to seven days after. Being that I'm only four days in I figure maybe that's why I'm still getting negatives because I'm testing too early. What do u guys think? How long did it take to get your positive after implantation? Please I need some advice.