Hi,
As a neurological cause of the brain fog has been ruled out for you, the reason could be a simple one like Nutritional deficiency, Anemia, Hypoglycemia, Hypotension or
Stress. It seems you have not gone for the routine investigations. Please consult a physician for the same. Please take adequate rest and exercises, eat a well balanced diet and take good sleep at night. Keep yourself away from stress. It may aggravate the symptoms. Hope this helps you. Take care and regards!