Does Medium Flow Of Blood And Only Brown Spotting Indicate Pregnancy?

I started my period about 6 days late, but it was only brown spotting. Later that night it was a medium flow for a few hours but then when back to just light spotting that was brown. I barely even needed a panty liner. This lasted for 3 days and completely stopped. I've felt sick in the mornings and thought I might be pregnant so I took a test and it came back negative. Sort of confused here...