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Change in sleep pattern and disturbed sleep may be a reason of symptoms. You are having lethargy and drowsiness along with numbness in body. These symptoms may occur in some form if nutritional deficiency
like anaemia, Vitamin B12 deficiency
may be a reason. Get you hemoglobin, B-12 levels, Thyroid horn in levels checked to rule out these causes.
If everything come normal then other possibility is mild depressive episode. Consult a Psychiatrist
for expert management.