He was definitely going to find another job. He'd told his girlfriend that part of him was scared stiff of getting married and they had talked it all over and come to a decision about what to do. John is an entirely fictional character although his story is based on fact. Any resemblance with a real person is purely coincidental. Anxiety and stress can make asthma worse.
Panic attacks can cause the level of carbon dioxide in the bloodstream to fall.
Recording your peak flow regularly will help to indicate whether your symptoms are asthma or anxiety. Don't be afraid to ask for medical help.