Hi Jemima37, I can only recommend that you take
@ryan31337 advice, get to the private Drs he suggests in London and get seen. Anxiety and agoraphobia can be reactive issues to the illnesses you have and not necessarily mental health issues in and of themselves. I had what seemed like agoraphobia for a few years - turned out it was the illness causing it.
If you try and carry on with the NHS you will, as far as I can tell, waste years of your life and get false hope and no help. Private Drs, specifically recommended by knowledgeable patients has helped me the most.
Your thyroid could well be undertreated and a really good endocrinologist such as Ryan suggests may be able to get to the bottom of the issue for you. Just going by blood tests is not enough and you may need more or different meds for it. Check out STOP thyroid madness.com for tons of thyroid info.
POTS can also run alongside other issues like CFS or thyroid issues etc and the cardio ryan suggested can rule in or out autonomic dysfunction.
I also live in Wales, and the health service is sadly lacking in any good specialists, even in Cardiff, nd I have to pay and travel to get help. If you can manage it, take some valium or similar and find some good help now. It will save you so much trouble later down the line.
Good luck!
Justy x