Millions of Americans have depression, and one of its many effects can be feeling tired all the time. "Depression is a common cause of fatigue and low energy," Dr. Haythe says. "Depression can take on many forms. For some, excessive sleep, fatigue, and an inability to get out of bed is common."
Depression is more than just feeling sad; if you feel like you have no energy to get out of bed in the morning and face your day, and find yourself sleeping for hours on end, Dr. Haythe adds, make sure you seek professional help from your doctor or a psychiatrist.
Chronic Fatigue Syndrome
Chronic Fatigue Syndrome is exactly what it sounds like -- people who are always exhausted, to the point where they can't carry on with their everyday lives. Although doctors recognize this is a problematic condition, it's still mysterious, and there are no tests available to confirm its existence.