You can ask for a physical. If there's any hemmorhoids get them to examine that too. You can get tested for h.pylori, standard blood tests to check your organs and maybe a colonoscopy. You can search for the nearest hospital to you that tests for tmau usually it's by a metabolic geneticist and ask the doctor to refer you to that. You can get a gastroscopy to look at your stomach and you can get tested for celiac disease and ask to get tested for food allergies .