Healthy morning,
There is not a test for fatigue and loss of appetite, but will review your medical history, perform physical exam and and other symptoms.
Blood test to search for potential conditions like hypothyroidism, celiac disease, CT scan or ultrasound for stomach .
Your diet is high in calorie, protein rich foods , or protein drinks easier on your stomach. Taking liquid form such as green smoothie or protein drinks may easier to stomach. If you have trouble big meals , you can also try eating small meals throughout the day to help keep food down.
Health Tips
You may feel less fatigue and have more energy if you eat a balanced diet of fruits, vegetables and lean meat, exercise regularly and sleep for at least seven hours each night.