Have you talked to your supervisor about it?
I ask because I’m a supervisor at Wal-Mart myself and if an employee comes to me with something like this I can usually find something away from people for them to do until they calm down and just having their supervisor know and accept it seems to help.
I have the odd panic attack at work too but working with customers usually makes it go away after a few minutes cuz I’m more focused on them than my chest.