Brief Answer:
Read below.

Detailed Answer:
I read your question carefully and I understand your concern.

From what I gather apart from the excessive sleep preceded by the headache there are no other symptoms such as fever, changes in behavior, confusion, weakness or numbness of the body on one side, visual problems, balance and coordination difficulties, nausea and vomiting etc. Those would be manifestations which would raise the concern of a brain lesion such as infection, stroke, tumor etc so in their absence shouldn’t be overworried.

Some viral infections such as mononucleosis can at times manifest with headache and subsequent fatigue and sleepiness which usually subsides gradually.
Rarely low thyroid function or iron deficiency may also manifest with sleepiness as well (but should be more gradual).
One other common cause are mood disorders such as depression. Some mood changes are more common during menopause due to the hormonal changes during this period.

So to resume while there doesn’t seem to be a cause for panic, if the issue persists some routine blood tests such as blood count, erythrocyte sedimentation rate, c reactive protein, blood glucose, liver and kidney function, electrolytes, thyroid function are advised. These are cheap initial tests to screen for infection and inflammation or metabolic changes which might contribute to such disturbances.

I remain at your disposal for other questions.

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Brief Answer:
You're welcome.

Detailed Answer:
I hope you'll be back to normal soon.

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