Do you have any problems with your neck or jaw ? Flying in an airplane can set it off ...
Tmj disorder ( jaw joints ) will cause severe anixety and millions of people have it !
http://www.nidcr.nih.gov/health/pubs/tmd/text.htm
http://www.tmjoints.org/
http://www.drshankland.com/tmj.html
I had a doctor try to tell me I was just a stressed out mommy when my girls where small. I ended up with whiplash in my neck and had to quit working at my data entry job ! I MADE him take an xray , he found the whip lash and sent me to therapy. At the therapy, I read about tmj and knew I had it ! Unfortunately, mine includes arthritis in the jaw joints.. I bet to this day that DOCTOR would still say it's just PANIC attacks.
Also severe allergies will make you anxious ! Air quality is dangerous where I live . How's your air ?
Oh research before you let a doctor say it's just panic attacks !