You're tired, weak, exhausted, weary, worn out. You have a lack of energy and as a result you feel distressed. You're not functioning as well as you should. It's called fatigue, and everyone feels it at times.
Acute fatigue is normal tiredness with occasional symptoms that begin quickly and last for a short time. Rest may help ease acute fatigue and let you return to your normal activities. Chronic fatigue syndrome (CFS) is a disorder that causes extreme fatigue. This fatigue is not the kind of tired feeling that goes away after you rest. Instead, it lasts a long time and limits your ability to do ordinary daily activities. Fatigue may also accompany other conditions, including pregnancy, anemia, or cancer, or may result from medicines or emotional problems.
Fatigue is a common symptom. Your health care provider can help find the cause and recommend ways to relieve it.
References and abstracts from MEDLINE/PubMed (National Library of Medicine)