Given the history of head injury
and the subsequent onset of symptoms of fatigue, you are suffering from possible consequences of head injury itself rather than multiple sclerosis
You are having frontal lobe
lesion on MRI which can explain the extreme fatigue, excessive sleep and sometimes depression
like symptoms or low motivation to do any work - which may happen in some patients with similar histories.
You may consult a neuropsychiatrist/ behavioural neurologist
in your area who can help you appropriately with medications. There are medications that can treat depression, extreme fatigue, low motivation or excessive sleep - all consequences of frontal lobe injury. Your neuropsychiatrist will interview and make the right decision.