Low salt levels can cause many symptoms. I get ocular migraines, fatigue, 'out of breath' , slurred speech. Salt fixes them. FWIW.
Dysautonomia is an umbrella term used to describe several different medical conditions that cause a malfunction of the Autonomic Nervous System. Usually excessive or overactive ANS actions occur. There are several different types of dysautonomia. Because it can be so varied, it can be difficult to diagnose. It can be primary or secondary. It is helpful to narrow down specifically what the origin is so that you can adequately target treatment. Prognosis is directly related to the type. So, this is a very difficult question to answer. My thoughts are that further testing would be a good idea to fully understand the situation and to get the best plan moving forward. We are very sorry you are in this situation. https://my.clevelandclinic.org/health/articles/6004-dysautonomia