"A Gift from the Heart" I am sending you in the link below to a heart transplant journal which I found very inspirational in my early scary dark days(liver transplant 1998). My suggestion is that you look at the different chapters and pick and choose what speaks to you at that moment, feeling commonality with the subject.
You are so right, the moment you realize that you went a few minutes without fretting over your body is the moment your mind/brain realize it can fly free again. That is when you can start re-inventing yourself as a healthy person. The people in your environment will need to be retrained to treat you as such, no longer sickly. It is a roller coaster ride but well worth it!
https://www.rjwitte.com/changeofheart/GiftFromTheHeart/