If i poo and blood and stool come out should i be worried?

Blood in stool: Blood in the stool is called hematochezia, and there are several causes for this. Small amounts of bright red blood in the stool is commonly caused by damage to the blood vessels lining the rectum from constipation or other trauma. Rectal bleeding associated with large amounts of blood, weight loss, fever, vomiting, weakness, etc. is cause for concern and should be evaluated by a physician.

Possible Colitis: If the condition continues, you should see a gastroenterologist. At your age, the concern would be colitis. Other possibilities are a rectal fissure (small tear) or a hemorrhoid. Another possibility is infection. If your symptoms continue for more then 10 days, see a doctor.