Hi and welcome:)
There are a couple of good answers on these sites:
http://www.ssa.gov/disability/professionals/bluebook/12.00-MentalDisorders-Adult.htm
http://answers.yahoo.http://answers.yahoo.com/question/index?qid=20080705181015AAXCtyN
Basically, laws differ in each state, but you should go about getting written documentation from your doctor (psychiatrist) that you are unable to work due to debilitating panic disorder.
Good luck and post anytime.
Scaredy Cat