Should I be worried about lung nodules?

My doctor found nodules on my lungs and said it is probably nothing to worry about and that I needed to be monitored for two years having CT's done. I have had my second CT and it showed the nodules had increased in size. I have also noticed small amounts of blood in my sputum. I am 55 years old. How concerned do I need to be now, because I moved and I no longer have that doctor and have not had my next round of CT's done?