I get anxiety attacks sometimes, particularly in stores. I have found that "square breathing" helps, if/when I recognize what is going on and have the wherewithall to do something about it.

Square breathing is VERY simple. It is all in "4's" - four things to do with 4 seconds each.
1-Breathe in for a count of 4 seconds.
2-Hold for 4 seconds.
3-Breathe out for 4 seconds.
4-Hold for 4 seconds.
Repeat at least 4 cycles - you do have to keep breathing! It often only takes a minute or so to get refocused.

I have a problem shopping. Often the anxiety is there, but I don't realize it and don't do anything to help myself. It can be embarassing. I go into a bit of a trance. I can stand and stare at a display or product in my hands for 10 minutes without moving. It it exhausting. It takes all my will to finish up and go home. When I get home I often have to take a nap to recover from the process. It's very weird being nuts, sometimes.