Spotting question 9 days after period

Kayla G
Hey all..
​I've been off the pill since August and had fairly regular cycles (from 28-36 days) never any spotting in between.. Even when on the pill. 9 days after my period I began spotting brown ... Enough to have to wear a liner for about 2 days... This is supposed to be my fertile week and so far all my ovulation tests are negative .... Any thoughts or anyone ever experience this?? Just very strange for me and never experienced it before..  Thanks!!