I am sorry this happened to you (sorry for all those suffering). However there is no value or utility in contemplating what you would've could've should've done. The past is gone; however you can still change your future. I struggle with this myself, but guilt or worry is not only useless, but it takes away the energy you should be directing towards your recovery.

I refuse to resign to an opinion that I may not fully regain my cognitive functions. A doctor's opinion is exactly that: an opinion. It is an opinion based on science, which has yet to understand much of how the brain works. However, there are exceptions, scientifically inexplicable recoveries, spontaneous healings. I will be an exception. I will recover or die trying.

EDIT: sorry a bit of a rant at the end...