Have been thinking about this again today and a couple of more things spring to mind:

It may sound harsh, but sometimes you may need to make the judgement to stop a conversation and walk out of a room, just to stop the flow and divert her way of thinking.

Someone suggested you do a bit of 'ahhh-ing' with a cuddle, which may be good to show support, but not all the time, as any feelings of helplessness and feeling weak might be reinforced by such actions.

Also, if you are not getting anywhere fast with her GP, and any consequent referrals (the NHS system is packed, and can take aaaaages to get any further, specialist help such as appointments with community nurses, psychiatrists, etc), it might be worth having a look at any private health schemes you might be part of, at work, for example. This will ensure she gets the help she needs much more quickly. I know it's not a nice way to think about things, you may as well get the benefit, as a 15 min consultation can cost around £80-100, so any subs you have paid will soon be worth it.

Above all else, you know your wife best, so you will know how to handle it best. It is so difficult to give advice on here sometimes, as only snippets of a situation are given, and not the whole picture.

Do let us know how things go on :)