Firstly,
to you for your condition(s) and hope you're coping ok each day.
I have extensive experience as a patient in mental health services for depression, and latterly addiction.
My word, everything you say rings true and YANBU.
NHS mental health provision is excellent compared to most countries in terms of coverage. What it clearly lacks however are nuanced, considered psychologists who look at a person as a whole and not as a person to take through various tick boxes and stages.
They are great (so to speak) with both extreme ends of the scale. So when people who come in with physical self-harm, or acute mental health, you can be placed into a facility and monitored monthly by the ward psychaitrist. Conversely if you're suffering from depression and see your GP, you can get onto a CBT course and get meds .
However for someone like yourself with a more nuanced and considered set of challenges, they struggle to know which box to funnel you off to. It's horrible as a patient because you get told different things every time, you get exasperated psychologists saying "I can't see what's wrong". Actually, that doesn't mean there's nothing wrong - it means they can't see which box you fit in.
Sympathies to you OP - my advice is to keep at it, keep trying until you find the right person who can unlock some sort of diagnosis or treatment for you. There are ways of self-referring to other services, ask your GP or local NHS trust.
And of course if the worst, and you feel dreadful, go straight to A&E please, don't bear the burden alone.