Peter, Did anyone bother to isolate your infecting virus? If anyone else of lesser credibility had told me your story (serious clinical disease after both prior infection AND the first dose of Pfizer vaccine), I would have been skeptical; the odds are so heavily against that sequence of events. It raises the question whether your second illness was caused by an antigenic variant virus that eludes antibodies induced by the vaccine and by prior infection with the wildtype strain, which is why I ask whether anyone took a sample of your secretions during the acute phase. It is vitally important that antigenic variants are verified and documented. I would go so far as to say that yours is a reportable case, if the data were available on which to base a report. Was your first case proven by a positive PCR also?
What's most important is that you are in recovery. Take your time. And obviously we are all so happy to know it, including me.