Thanks for your question on Health Care Magic.
I can understand your concern.
In my opinion, you should first get done PFT (Pulmonary Function Test) to rule out bronchitis
Your current symptoms are more in favour of bronchitis. You had history of smoking
. And bronchitis is more common in smokers.
So get done PFT first.
It will also tell you about severity of the disease.
You may need inhaled bronchodilators and inhaled corticosteroid (ICS).
If PFT is normal than possibility of stress
related breathing difficulty is more.
So consult psychiatrist
and get done counseling sessions.
Don't worry, you will be alright. But first diagnose yourself and then start appropriate treatment.
Hope I have solved your query.
Wish you good health. Thanks.