How do you know if symptoms are anxiety or neurological or something else?

So in a nutshell for the last 5 years I’ve felt unwell with no apparent cause.

I’ve been neurologists, rheumatologist, psychologists, GP’s and counsellors and I don’t fit into a particular category.

On a daily basis I suffer with: Chronic pain all over my body and even on touch. Twitching muscles, Tremors, Stiffness, Minor urinary incontinence Blurred vision including blue flashes, Low mood

In recent months I’ve had problems with balance especially in crowded environments.

I’ve had so many tests including EMG’s, nerve conduction tests, specialist blood work to rule out things like my thyroid and Lyme. I’ve tried sertraline and amitripyline and had no benefit or ill affect

Any ideas? It started during Covid but don’t ever believe I’ve had Covid or any major life event?

I’m in my early 40’s and feel like an old man