First rheumatology appointment today. Scared

Just like the title says, I have my first rheum appointment today and I am scared. I’ve been suffering for 5 years now with debilitating symptoms and doctors have either dismissed me as anxious or not been able to find the cause or a treatment that works well enough to give me quality of life. Finally, my GI referred me to rheum because he’s suspicious that what’s going on with me is systemic and possibly autoimmune. My Gynecologist is also pretty sure it’s autoimmune or adjacent. But…. I have had a long history of doctors not taking me seriously and dismissing me outright because I have anxiety and I’m scared this guy is going to be the same.

What are rheumatology appointments even like? What questions should I ask? How much detail do I need to give? Sometimes when I get nervous I definitely talk too much, and I don’t know what symptoms are even relevant.