If something were wrong with your lungs a x-ray would have shown it. That is how the doctors realized I had something wrong with my lungs, and after more testing found out I had sarcoidosis. You're lungs are fine... Listen you have anxiety, you need to get help. I completely agree with nursegirl, and once you get the help, and take the steps to get better you will enjoy life so much more.
When was the last time you saw your doctor about your anxiety? Did your doctor tell you to start taking the Ativan again? The problem with depending on Ativan to manage your anxiety is that one, it isn't enough and it doesn't make the long term changes in your thinking and reactions, and two, if you take it with any kind of regularity, you will build up a tolerance to the medication, which means you will need more and more to achieve the same level of effectiveness you initially experienced.
You say frequently that you try to handle anxiety on your own, but to be honest, you've not managed to do that, at all. At some point you're going to have to accept that you need help with this, and more help than just being prescribed an anti-anxiety medication, which will only give you very short lived relief.