Hi Samantha,
Sorry to hear you've had a little setback. Please don't be discouraged by this, it's absolutely normal and to be expected on your healing journey. These little hiccups never last long, just relax and try not to read too much into it. I found that trying too hard to understand what was going on, caused stress of it's own, which is what you want to avoid. TMS is a subconscious habit that you're working on breaking, your brain's just trying to revert to it's old pattern is all.
The key phrase in your post is
"I'm afraid that my progress is a 'house of cards'." It's the fear of your symptoms that perpetuates them, once your lose the fear of your symptoms they have lost their effectiveness as a distraction, so being redundant will inevitably fade away. Lose the fear - lose the pain, it's that simple.
The thing that helped me the most when I was at the stage you are was following the advice of Claire Weekes in her book "Self Help For Your Nerves", her CDs where a huge help too, I still listen to them to remind myself that TMS is ultimately harmless and powerless. I would highly recommend them.
Trying too hard is another pitfall we can get into, let healing come to you at it's own pace,
you have made fantastic progress, just keep going and be kind and patient with yourself.
Bless you
