Suffering from derealization, anxiety and depression in fear of repeat of an attack in which lost physical control and thought I was dying or dead.

PTSD. Your description sounds like it's possible that you're suffering from ptsd. I'm sorry you've had this experience, but there is help. Work with a psychologist skilled in emdr and cognitive behavioral therapy. Additional therapies may help also, including somatic experiencing (developed by peter levine). If needed, some medications may help with symptoms -- but they alone aren't curative.