wake up with a headache or have one shortly after waking, low body temp, chills, but feel feverish, 47, male, no meds, was taking niacin daily at 25 mg, about 3-5x daily to aid in weight loss/cholesterol reduction, roughly about 50lbs, overweight, just started a swimming exercise class and have gone 3x this past week, always feel like I'm freezing at night and cannot get warm, some nausea,