Secondary Conditions for Tinnitus/Hearing Loss/Vertigo

For the past six months I’ve started experiencing mental health issues like insomnia and axiety secondary to my current disabilities of Tinnitus/HL/Vertigo. I plan to schedule a private doctor appointment this week to discuss my symptoms and have no idea if it will result in a diagnosis until I meet. I’m curious if any others have filed secondary conditions similar to these service connected disabilities of Tinn/HL/Vert? My VSO said I would need a nexus statement but I’m pretty sure private doctors won’t do that. Has anyone been able to obtain a nexus statement and if so from who? Also VSO said the doctor would need to state the following on a letterhead that those conditions were "MORE LIKELY THAN NOT" caused by Tinnitus/HL or Vert.

Anyone input is greatly appreciated.