Hi. Thanks for your query. Noted the history and understood your concerns. Fullness on small quantities of food, loss of appetite, fatigue, loose motions after taking Omeprazole not responding to Lomotil indicate that you are most probably suffering from Gastroenteritis. I would advise you the following: Send the sample of stool for tests and blood for routine investigations. Clinical evaluation by your Doctor and get a course of an antibiotic, metronidazole if there is an evidence of infection. Continue Omeprazole, take antacids, soft bland diet. Use only boiled and cooled water, homemade fresh foods. Take probiotics and electrolyte solution to tackle electrolyte imbalance and fatigue. Domperidone if there is nausea, vomiting or fullness.