Bloody Stools

So for the past two days ive been getting bloody dirrahea but im not on my period and im 12 days late so im sorta worried whether that is a pregnancy symptom or what?? Any answers or links that would help? Btw it looks very light watered down blood so it sorta looks pinkish and its only when i go to the bathroom, it doesn't come onto the pad like a period would so im scared its implantation because im 15.