My 3 year old daughter threw up black 3 times .. I took her to er soon as it happened the first time. They tested it positive for blood. Because it was black this ment it was not currently bleeding what ever it might be , so no ferther testing was done. My daughter has not eating anything but a cracker in 3 days and two cups of water/juice . She has had direah for three days. And has been crying about her back . What could this be ??! I m scared for her. She also has had a bad history or constipation which just happens before all of this as well ..