Obviously, no-one can confirm a diagnosis on here but with some exceptions I could put a tick against most of what you've written! I was diagnosed at 45 well over a decade ago.
It was not hugely recognised in adults then. My GP knew next to nothing about it, even in children, so I went to my appointment and took the line that I had something, I suspected it was ADHD, but whatever it was I needed to know. I also, up to that point, had been told at various times I was just depressed and been prescribed Citalopram, which frankly, made bugger all difference. Living with undiagnosed ADHD and a lifetime of low self esteem, failure to 'achieve' anything of significance career-wise despite apparently being of above average intelligence and wondering why I couldn't do the simple stuff that others seemed to manage, was obviously enough to make me depressed.
I've written elsewhere on here that I used to have really vivid nightmares which would make me wake up screaming and scare the crap out of my exH. Post-diagnosis I've had occasional bad dreams but nothing like the 'screamers', thank goodness, especially now I have a 'senior bladder!
Also, there is a tendency to think that all will miraculously be solved and calm and smooth with a diagnosis. Nope. The only difference was I spent less time wondering WTF is wrong with me, because now I knew!
And there is no guarantee that medication will miraculously turn things around either. Some people see a massive difference, some don't. Some meds work better than others, some might make a difference for longer than others. Everyone is different so it's trial and error. Also it can take a long time to be seen by a psychiatrist after referral.
Back then my GP agreed to prescribe meds if I got a diagnosis privately, as that was the quickest way to get whatever it was confirmed. I tried methylphenidate and an extended release version of it but didn't really feel any lasting benefits. I stopped bothering with meds and got on with life.
That all changed when the menopause struck - all my ADHD-ness worsened and the prover ial wheels fell off!
Went to my new GP (I'd moved and separated from exH). Referred to my local ADHD clinic and now under a shared care arrangement.
And it is common to go through a sort of mourning period; to mourn what might have been.
Some days I just can't think - my brain won't comply. Some days I have moments of total overwhelm.
LOL at verbal diarrhoea - I've no idea what that is off course...