The Centers for Disease Control have established a formal definition that involves criteria that need to be met for a diagnosis of chronic fatigue syndrome.
Chronic fatigue syndrome is defined by the presence of the following:
1. Clinically evaluated (i.e., evaluated by a doctor
and other things that cause fatigue such as thyroid disease or anemia
are ruled out), unexplained, persistent or relapsing fatigue that is of new or definite onset; is not the result of ongoing exertion; is not alleviated by rest; and results in substantial reduction of previous levels of occupational, educational, social or personal activities
2. Four or more of the following symptoms that persist or recur during six or more consecutive months and did not come before the onset of fatigue:
a.) self-reported impairment in short-term memory of concentration
b.) sore throat
c.) tender lymph nodes in your neck (cervical) or armpit 9axillary)
d.) muscle pain
e.) multiple painful joints that are NOT also red or swollen
f.) headaches of a new pattern or severity
g.) unrefreshing sleep
h.) malaise/fatigue that lasts for more then 24 hours after exertion
If you think you meet these criteria, you should speak with your doctor.