Blood in the stool can come from several reasons. It may be a colonic polyp that has become irritated and bleeding, hemorrhoids that are bleeding, or irritation of the lining from an infection such as a viral gastroenteritis or bacterial gastroenteritis.
Given that you are seeing blood in your stool and urine I would recommend that you be evaluated by your doctor to be sure that your clotting factors, etc. are OK as well as look for any other possible causes.
Advice and opinions given are based on the information provided and must not be considered an official medical recommendation. The limitations of the internet prevent an appropriate evaluation. Always consult your doctor if there is concern.