Why Does the Doctor Cut Me Off Before I Finish?
Experts stop listening the moment they believe they recognize the pattern, and they recognize it early. You get cut off because of: 1) the curse of knowledge, once he has a likely answer the rest of your details genuinely sound like noise to him 2) anchoring, since the first symptom you name sets the direction of the entire visit 3) the primacy effect, because what you say first is what survives into the notes and everything in the middle quietly does not. Lead with the thing that scares you, not the thing that started first.
What is actually happening
He pattern matches in seconds
Your first sentence sets direction
The middle sounds like noise
Say the scary thing first
How it actually plays out
Write one sentence down before you go in and see how the visit changes.