It sounds very much like you have celiac disease. This is a condition in which the body has an allergic response to the protein called gluten, which is found in wheat and other grain products. The allergy causes damage to the inner lining of your small intestine. The end result is abdominal pain
and cramping, and nutrient absorption problems. The body can't absorb fat, and thus it stays stuck in the stool turning it green and fowl smelling. Microscopic blood in the stool is common. There is also a skin disorder called dermatitis herpetiformis which is associated with celiac disease. The treatment for this disease is eating a gluten free diet.
I suggest that you schedule an appointment with a gastroenterologist
. He or she can review your history and get some basic blood tests looking for the antibodies associated with celiac disease. The disease will need to be confirmed by a small intestine biopsy which can be performed by endoscopy. This is where the doctor
takes a long telescope and takes a small piece of your bowel for examination under the microscope. It is very important that you do not change your diet prior to your appointment with the doctor. If you decide to try the gluten free diet without first getting the blood test and biopsy, then a diagnosis may not be made and no one will know what you have. Good luck.