Mark, my heart goes out to you & your family.
Don't despair, it's not confirmed yet.
Back to May, 2001. I too started suffering from shortage of breath and feeling dogshit. From being always being first at the sprint station in circuit training suddenly I was down with the plodders. Bike power just went out of me too. Ends up I'd got pneumonia, admitted to Queen's Park hospital Blackburn and had chest x-ray. Right chest cavity full of fluid. My then wife was told (unknown to me at the time) to expect the worst – C – and anything else was a bonus. Cat scan showed nothing I'm pleased to say other than empaema, basically an absess on the lung. I honestly thought I was dying. Chest drain fitted and wait for it to empty. Trouble was it had solidified and had squashed the base of the lung, hence shortage of breath.
Blackpool Victoria next for lung op, raked out all the crap. 4 months before I could go near the bike. Eventually the day came when I got my life back and started training again.
Guess I was one of the lucky ones. I'm back as fit as I was then enjoying life (I can still beat those kids on the sprints!) but never ever take my health for granted.
Hope you can draw a scrap of comfort from this and you get a good result on Monday.
Graham