Implantation Bleeding & Bowel Movements (sorry if TMI)

Hi all, TTC since Dec 13, VERY regular 28d cycle, 4/5d period until last month, I was 11 days late for period & when it finally arrived, boy did I know about it!! According to Glow today is CD29 & since CD26 I've had a very small amount of light pink/brown discharge when I wipe - but this only happens when I've had a bowel movement, when I go for a wee, there's no sign of the discharge. Could this be Implantation Bleeding? Help please :-)