A lot of physical problems can cause the same symptoms as anxiety disorder. I don't think the gall bladder problem was related to the anxiety but the procedure may have triggered chemical changes that triggered the anxiety. I'd ask your doctor next time you see him for follow-up if the anxiety could be related to any other illnesses.
Check this out; the doctor's answers especially:
http://www.medhelp.org/posts/Gastroe...es/show/236456