Hi Dear, Welcome to HCM. Understanding your concern. As per your query you have symptoms of diarrhea, blood in stool and gastritis, Well there can be many reasons for symptoms you mention in query like gastroenteritis , food allergies , lactose intolerance , giardiasis , irritable bowel syndrome or appendicitis. Need not to worry. You should exercise daily and should not lay down immediately after having food. For now eat light and non spicy , take antacid after every meal, drink plenty of water and take light walk after every meal. I would suggest you to consult gastroenterologist for proper examination. Doctor may order ultrasound , endoscopy or stool test. Doctor may prescribe omeprazole , laxative , ornidazole or albendazole. You should take small and frequent meals and avoid taking large meals at at time. Hope your concern has been resolved. Get Well Soon. Best Wishes, Dr. Harry Maheshwari