Help!

So on the 8th of this month I was working night shift and I went to the restroom and I wiped myself and I had an egg white consistency of CM and light brown color blood. Just once. it's now the 9th and it hasn't happened again. could it be implantation bleeding? I took a test when I came home yesterday morning and it was negative, but I researched that even the most sensitive of tests won't detect pregnancy for 2-3 days after implantation, so I plan on taking a test on the 11th. Has anyone have this happen before and end up pregnant?