You my find some hope in the following thread which is also on this forum:
http://www.medhelp.org/posts/Respiratory-Disorders/Lung-Nodules/show/1055851
It is very long, you may want to start toward the end, that's where I have the most familiarity.
The good news/hope you may find there is many people who have lung nodules found in a CT scan, do not have cancer, in fact do not have anything that needs treatment. The reason for the delay between CT scans, beside not exposing you to unfruitful radiation exposure, is to give the nodules time to change. If they don't change, are dormant, then cancer is not at all likely. If there is a growth a needle biopsy may be indicated - you'll see that discussed in the bottom of the above thread.
Be positive, as you said: you have a healthy life style, are young, and have every reason and need to live - positive faith in yourself and your doctors will help.