The past 3 days my sons (17months old) poop has been blackish with shade of green. It looks like tar and like spinach that's been digested he does have regular color sometimes...I hear black poop means internal bleeding. Also I don't feed him ANYTHING that would give him this type of poop and I am POSITIVE it can't be anything he eats. He is active, no vomiting, no fever. He's is as happy and playful as can be. I'm just a little worried, any already moms had this with there children ?? Should I be worried?