Mathew Amschler wrote: What should I do next?
Go out and get involved in life. Take some risks. Join some clubs. Volunteer. Interact with other people. Get off the Internet. Get active in participating in a wide variety of projects. Fill your life with different goals.
A person worried about breathing typically has too much free time available. The person typically has a comfortable bed, plenty of food, electricity and lacks for no basic necessities. This gives them too much time to think, to surf the Internet, and to become less than fully engaged in life.
Not being engaged creates a vicious downward spiral as individuals lose self confidence, become anxious, and then retreat further into isolation.
As a person becomes engaged they don’t have the luxury of time to think about all the mental monsters out there. The same will work for you. Stop thinking and start doing.