I had Pneumonia 3 years ago when I was 37.
Completely knocked me for six. I had 8 courses of oral antibiotics and once the GP finally suggested I needed to go to hospital I started getting better. Having been bed ridden for 4 weeks and loosing 2 stone.
Better was relative though. It took me about 3 weeks before I could walk at more than snails pace, or go up stairs.
For about about 1 year after the slightest cold in anyone else, I would be floored and ill for days.
The only thing that worked for me was sleep and more sleep, and being patient and realistic with what I could do exercise wise
After about 6 months I was back doing light exercise, a bit of turbo and slow jogs. Noting hard. But then I would more often than not get ill after.
Even now I am not looking forward to winter as I appear to be more susceptible to bad colds in the winter.
My advise would be take it very slow, dont rush back to exercise give your lungs chance to fully recover.
I assume your will be called for a follow up chest Xray too ?
However 99% of the time I am nearly as fit as I ever was, but it just feels harder to get fitter and I am not sure if that is the result of Pneumonia or getting older 😆