Never having smoked, the likelihood of this spot being lung cancer is extremely low. That doesn't mean it is zero. So you should have the follow-up CT scan in 3 months. There is no way not to be a bit worried about this, but you shouldn't lose sleep over it, especially since the spot is small.
It could be just scarring from a previous infection. The purpose of a follow up CT in 3 mos. is to see if it is growing. If it hasn't grown, it is most likely scarring. If it has grown, well then it will be time to worry. Until then, just try to relax. You have no control over it, so why stress yourself out.