Thanks for providing more information.
Well as you describe excessive sleeping,dizziness,lethargy,weight gain -such symptoms shouldn't be ignored.
And you need consult your regular doctor for a clinical examination and undergo Chest X-ray, blood work like CBC,ESR,Thyroid function test, Absolute Eosinophil count,24 hr urine cortisol to rule out underlying possible causes like Anemia,Thyroid dysfunction, imbalance of cortisol,Sinusitis,Bronchitis,Allergy.
Atenolol may be contributing to the cough by causing broncho constriction which is the side effect of atenolol.
So discuss it with your doctor.
You should start a multivitamin supplement containing B complex.
Also hydrate yourself with plenty of fluids.
Do saline gargles and steam inhalation.
Cough more than 2 weeks shouldn't be left untreated.
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