B.C.
Tiffany said what I was about to say. Could be nothing (most likely is), but with my 2nd pregnancy, I started early. For some very strange reason, I decided to buy a pregnancy test. Just a whim. It was positive. I spotted brown/light pink for 10 days before I got the extreme pain and had to have emergency surgery to remove the tubal (ectopic) pregnancy.
I am NOT telling you this to freak you out, but just keep in mind that abnormal things like this should at least be discussed with your doctor.