First, congratulations on 12 days of sobriety, it is great that you are feeling better.
Forgive me if I have misunderstood but what you describe sounds more like an existential crisis rather than a fear over lingering health issues.
Having read your words that way I immediately thought of the wonderful, wonderful psychologist and author Irvin D. Yalom. He is a specialist in existential psychotherapy.
Here is a short paragraph from one of my all-time favorite books (by anyone) "Love's Executioner"
"I have found that four givens are particularly relevant to psychotherapy: the inevitability of death for each of us and for those we love; the freedom to make our lives as we will; our ultimate aloneness; and, finally, the absence of any obvious meaning or sense to life. However grim these givens may seem, they contain the seeds of wisdom and redemption. I hope to demonstrate, in these ten tales of psychotherapy, that it is possible t confront the truths of existence and harness their power in the service of personal change and growth"
I gained an immense amount from reading this book, although for reasons unrelated to fear of death, and would highly recommend it to absolutely anyone. I think that anyone could gain something from reading it, but your comments made me think it would be particularly of interest- and hope and help- to you.