I am worried

If you do the research you will find that COPD takes 40 to 50 years to develop. If you think back to your childhood and remember if you ran out of breath when doing things like shoveling snow, or unable to run long distance, always congested etc. then that may have been stage one of COPD. I am in stage 3 and now find extreme fatigue to be the worst part of it. Smoking can bring you to the next stage quicker, however it is not the cause. Ironically smoking becomes a double edged sword. The people I have talked to who have quit smoking all have a difficult time expelling the congestion they have and are only able to cough up teaspoons. I am finding that as well when I do not smoke, but find that when I do smoke the irritation caused by the smoke allows me to expell far beyond the teaspoons. Clearing the congestion is key in being able to breathe and possibly delay having to use oxygen. So look at your history first. If you have COPD you first got it as a child.