16 year son becomes lightheaded, cold sweat and limbs feel heavy in middle of physical exertion. nationally ranked athlete in great shape. has hashimotos=on 175 mcg synthroid. often happens after a snack of carbs (e.g. bagel) yesterday happened after peanut butter/honey wheat bread sandwich. tested neg for celiac. he came off the court during a normal practice and found me. he was dripping in cold sweat, told me his limbs felt they weighed a ton, very pale