Hello @lola1971 and welcome to Mayo Connect. As I was unfamiliar with SIADH, I went online and found some information from WebMD. Here is a link that explains it for others who might be interested.
\https://www.webmd.com/a-to-z-guides/what-is-siadh

Could you share a bit, as you are comfortable doing so, what symptoms led to this diagnosis and how you are feeling now?