What is ME/CFS?
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome is a diagnosis of exclusion, which means you cannot test to see if you have it or not.
Based on the diagnostic criteria published by the National Academy of Medicine in 2015 which is cited on the U.S. Center for Disease Control's (CDC) website, you may be suffering from this condition if you experience the following symptoms for over six months or more:
Profound, unprecedented fatigue.
Fatigue that is not a result of ongoing or excessive exertion.
Fatigue that does not ease with rest.
Unrefreshing sleep.
Worsening of symptoms after physical, emotional or mental exertion which would not have been a problem beforehand.
Brain fog.
New inability to process information quickly.
Increase in brain fog, fatigue, nausea, dizziness and/or palpation when standing and walking.
https://www.cdc.gov/me-cfs/healthcare-providers/diagnosis/iom-2015-diagnostic-criteria.html