Hi Jake,
I'm glad to hear of your good initial results.
The pain lessoned by alot the next day.
This is not uncommon and is a great support for your work.
"Believing," in my experience is central to process, as you suggest. Everyone finds their certainty in their own time and way. We build up trust in the diagnosis and in the process and in our practices to address TMS. More confidence is part of the "fuel" for your journey.
Should I be doing more to convince myself?
How one does this varies a lot. Keeping a list of all the evidence, the results, the little breakthroughs and reading them daily is helpful. Reading success stories helps. Reassuring statements, affirmations help some. Re-reading phrases from Dr. Sarno's books which really speak to you can help. Placing yourself right back in the moment of your initial success, the feeling, the affect, the sensation in your body can be great.
Putting pressure on yourself to "believe" more, faster, better is probably not helpful. I recommend doing it gently and inquiring into your doubts. It is a wonderful thing, confidence in the process, trust, because it removes fear. But it isn't something you magically create. It is part of what is needed.
Andy