Jess,
Panic attacks are part of this process. Let me assure you, we all survived. Breathing helps but the best cure only happens the day AFTER surgery. All the panic and crazies suddenly disappear
A bone density test is absolutely painless. You lie on an exam table, fully clothed, the machine passes over you, end of test. No films. One less thing to worry about.
Seriously, I know how you feel. I realize it doesn't help but this isn't a nose job, it's serious body altering surgery. Stress is part of this disease and part of the cure. Even after surgery, a little blip will send your mind into overdrive. If you know how to meditate, I suggest it. If not, take some time to learn relaxation techniques... deep breathing, relaxing your muscles. (pm me if you'd like specifics). It helps a lot more than you'd think.
Good luck
, Dale