Yeah, I had a therapist who had pneumonia and got extremely sick. She was on a ventilator for ages and afterwards when she was in the rehab facility, she said she developed panic attacks related to fear that she would be put on a ventilator again. She said it was like never being able to get enough air or like being suffocated.

I know her lungs were damaged, as well, because they kept removing chunks. Hopefully your therapist isn't worried because she has reduced lung capacity.