Spotting while pregnant?

I have been TTC and this month my period was expected on the 30th...it is now 10 days late approx and I just started spotting very light (pink and a little brown). I have taken tests after 1 week missed period and it said negative. :/ I read that some women don't have positive pregnancy tests until 10-20 days after a missed period. I'm just wondering if anyone experienced spotting before a positive test or if it's more likely to be a super late period.