Do they have a human resources department that you can talk to besides these supervisors? Maybe they would be able to help you more in these instances where you have your panic attacks. Have you tried other things like taking bathroom breaks in order to collect yourself or maybe stepping outside for just a moment to breathe? It doesn't sound like you have any real method of being able to hold your composure together. If you need any advice about the matter, shoot me a message.
I used to give one of my really good friends crap for trying to drink her problems away, now I feel like a hypocrite because usually the only time I feel happy now is at the bottom of a bottle.