Ruling out addisons disease what other conditions would cause me to excessively crave salt? I get up in the middle of the night & eat salt by the tabl

Not common. Sx of addison's disease can include: craving salt, muscle weakness, fatigue, weight loss, low blood pressure. Salt craving can also be seen in bartter syndrome and certain psychiatric conditions. Check w/your doctor for help as severe salt craving is obviously abnormal.
Low hormone levels. In chinese medicine, salt is the flavor of the kidneys. If you crave salt, the thought is that you would be low in kidney energy. Kidneys rule your hormones according to chinese medicine, so it could be any other hormones, or you may be taking the birth control pill? Which would throw off your hormones.