This is a concerning symptom that should be assessed by your primary care doctor
. While sleeping this much itself is not likely a problem -- the big issue is why you are sleeping this much. The fact that your have symptoms of fatigue and feeling tired is concerning as this can be a sign of a number of disease. I would STRONGLY recommend that you discuss this with your doctor.
There are many causes of this fatigue that should be ruled out. Many of these depend on your age, gender, medical history and physical state. For example, in young women one of the major causes of this is anemia
-- which is a low blood count. However in older women a common cause can be hypothyroidism or low blood levels of thyroid hormone. The thyroid hormone is the "energy hormone." In overweight men and women a common cause is obstructive sleep apnea
-- where people have decreased breathing at night because of excess tissue in the neck so they do not get a restful sleep. Another common cause in all people is depression, which does have other symptoms but excess sleep is very common.
I would strongly recommend that you discuss this with your doctor. This should be evaluated.