"I feel at times I'm going one step forward and two steps back."
Such can be the nature of TMS healing. We actually teach ourselves the most on the days we feel we are struggling, because it's about how you approach the struggle.
My best work is done on those days when I can say "today is just a DAY" and do my best to get through it without fighting the symptoms, without resisting the difficulties, and having some self-compassion. Tomorrow is another day. This is the most calming thing you can do, and over time you'll train your mind not to freak out on rough days: you may have symptoms but you won't have so much emotional suffering: anxiety, worry, fear, fixing, focus etc. over them. This is actually a very large part of the work. Trying to "calm" yourself is another method of fixing - and although I haven't read the book you are reading, I don't think it's a method the author would suggest because forcing yourself to calm is using willpower.
There is often more to the occurrence of symptoms than a simple association of emotion. Sometimes the brain simply expects pain because pain or symptoms become the brain's habit. When you are in the thick of it, there isn't anything to "do" - it simply just is. That can be hard to experience, and hard to understand because we've learned to associate the symptoms with something is "wrong" or a "problem" but some days are just hard and we don't need to figure out why, or even worry about if it's the work or isn't the work or worry about any cause/effect because the simple answer is Who Knows?!
It's like your dreams. Dreams are just dreams, and it sounds like your mind might be sensing you clinging to the idea that there is something "wrong" with your dreams and you've had some fear of them. Dreams are dreams. You can't control them (which is the beauty of them), and they can't hurt you. Just let it go.
Things I "do" on days that are challenging: Recognize that "doing" won't solve a single thing. Reminding myself that healing has phases and this too will pass (which is hard, but it does pass). Finding things I can do regularly to help my nervous system (not everyone likes to do his, or even recommends it - this is a choice) and not just on "hard" days but on many days: meditation, walking and looking at nature, sitting quietly, listening to music, getting up to walk or move every hour or so, engaging in any kind of hobby or enjoyable busy work, (even if it's not enjoyable in the moment or hasn't been for a while) Sometimes it's even hard to enjoy the things we used to do - it will come back over time.