I need help! how do i know if i have gastrointestinal problems?

Tummy problems: The short answer is, you'll know. Symptoms typically arise with GI problems. Abdominal pain, nausea, diarrhea, constipation, anorexia, vomiting with blood, or painful bloating. You can also have symptoms from malabsorption. For example, tired and weak from anemia caused by iron/folate deficiency. If you are having symptoms, it would be a good idea to discuss them with your primary care physician.