They keep saying it’s “functional neurological disorder caused by anxiety”. Which basically means “it’s all in your mind”.
I know it can be symptoms of perimenopause, and I have other peri symptoms like flooding periods and dry eyes. But they just keep saying I’m too young.
Functional Neurological Disorder is a diagnosis made when all other possibilities have been excluded. It doesn't mean it's all in your mind. Have you investigated this further? There is also a condition called Benign Fasciculation Syndrome. This is also linked to anxiety. It sounds as if you may have both of these syndromes and they do often occur together. It is not an imaginary illness but the physical symptoms are caused by underlying anxiety. Sometimes sufferers feel as if they have MS or MND.
Taz x 
That's the diagnosis my son got, either that or peripheral hyperactivity syndrome from the neurologist. He should have had a test but covid struck and by the time they started up again he decided he'd not gone worse, nothing bad had happened so he accepted it was one or the other and has learned to ignore it. He suffers from anxiety.
Aeniad, you have choices, you either accept the doctors diagnosis and try to address the anxiety and review your symptoms or you pay for a private consultation. Otherwise you'll go round in circles increasing your anxiety and panic and make yourself more ill. You are doing what people with anxiety do; they ask different people because they dont believe what they've been told, youre hoping to get a different answer that makes sense.
If you really are suspicious of your diagnosis, see a neurologist. It costs around £250 depending on individual consultants however tests and review appointments are extra.