OP, I think that if you're already dealing with things like anxiety and associated paranoia, that the metal tasete in your mouth that you mentioned could easily be psychosomatic. At any rate, I feel pretty confident in telling you that you're fine. There's nothing to suggest that you're in any kind of trouble or that you're experiencing a bad reaction. I agree with d1nach in that you should probably find a way to endure your panic attacks without resorting to the Emergency Department. To each his own and I don't mean to minimize your situation, but it's really nice to not have to deal with the ER every time something like this happens.
One thing that comes to mind is that Hydroxyzine (Vistaril, Atarax), like other sedating antihistamines, definitely can cause dry mouth. Having a dry mouth, I feel, could definitely produce sensations/tastes like the ones you have described. All things considered, I think that you're fine and you don't have anything to worry about. I think your anxiety is just getting the best of you. It happens to all of use sometimes!