Brad, this might not be very comforting, but you have to consider that your terrible hit was a sign that the busting is working. These kinds of unusually bad "slapbacks" are part of the process for many (or most) people, and they're the best indicator we have that the busting had an effect. I really, really hope that's going to turn out to be true for you. The standard wisdom here is that typically the slapbacks are less bad after the first couple of busts.
You seem like a person who would have diligently tried practically everything, but I have to ask along with xBoss about whether you have tried optimized oxygen (properly high flow rate, top-quality mask, best breathing technique) and whether you're doing the D3 regimen. (And some other possibilities, such as Benadryl or Quercetin, energy shots, etc.)
I know there are a lot of people here feeling your pain and wishing for better days for you.