What Causes Excessive Craving For Salt And Persistent Headaches?

I am a 31 year old, otherwise pretty healty female. I have been dx'd with Hypothyroidism and PCOS. I have always liked my food salty, but am now noticing that I crave salt. I can go home and literally sit on my couch and eat popcorn salt. I always get headaches and have always had an issue with low blood pressure and hypoglycemia. Should I be concerned about any particular disease, example: Addison's Disease????