11 days late...now im lightly spotting dark brown. What dows this mean?

I an 11 days late today. I went to the OBGYN for blood work today, but won't get my results until tomorrow. Go figure, I just started spotting! it's very light...and it's brown. Has anyone else experienced this? Hoping I'm pregnant, but now I have my doubts. Oh, and I've taken like 10,000 pregnancy tests and they're all negative. Even the First Response Rapid Results tests...