Spotting for 13 days

I have been lightly spotting brown or pink blood for 13 days. Super unusual for me. The spotting started 6 days before AF was due. AF was due on Sunday August 9. Oddly I had no spotting on the 10, 11 and 12. Then on the 13th it resumed until now.  I had a sono which came back negative for ectopic at the time. Pregnancy hormone was low. They said to come back on Aug 24th. Of course I've been testing like a maniac and all are positive with faint lines. Digital said 1-2 weeks. Has anyone else experienced this?