Chronic Fatigue Syndrome
Chronic Fatigue Syndrome is a severe disabling fatigue lasting atleast 6 months for which there is no medical explanation. 
Main symptom of this disease is constant feeling of being tired, severe fatigue, muscle aches, sleep and mood disturbance. Other problems such as heart and chest problems are not medical reasons that would cause fatigue. The feeling of fatigue goes on a constant basis and is usually overwhelming to a point that an individual has a hard time continuing with normal physical and mental activities. Many conditions can cause tiredness therefore there is no simple blood test for Chronic Fatigue Syndrome.
Other common illnesses that may cause you to be tired are anemia, heart disease, depression, and low thyroid gland function therefore it is important that you don’t have any of the other conditions that may cause you to feel tired.
