I know EXACTLY how you feel. I get the same way, especially at Walmart( Although have had it happen at Kmart as well) and I definantly can not do malls at all..YUCK! Anyways.,.what I do is start out small. Go to a drug store, convenience store..etc. Have your hubby stay in the car the first couple of times, and just run in for milk, bread, pop..whatever. It is a small thing, but if you can manage that, it truly gives you confidence to work your way up to a big store. Walmart always gives me fits. At my store, they keep it way to hot, so when I start to sweat I think there is something wrong with me. Course, this has happened SOOO many times, I know by now there is nothing wrong. Walmart is always crowded so that might be what is setting you off as well. What I have learned to do it just IGNORE how I am feeling. When I get feelings of panic, I just say to myself..ok, now you know you have had these feelings before, you didnt die, so you wont this time either. And I tend to just relax myself and try to steady my focus on ONE thing. That way your head isnt spinning looking at ten things at once. Really, the only way to conquer fear of going to Walmart, is to go there and face it. Sometimes I just concentrate on WHY I am there, to do a task( grocery shop for my family so they can eat) and when you concentrate on other people, sometimes that fear does tend to subside. And you get the strength to do what you need to do.
I think why stores are so hard to deal with is...,.we are among strangers and the last thing most people want is to have a panic attack, heart attack, or other problem arise in the midst of people we dont know. We feel crowded in upon, and that feeling can be very overwhelming. We dont want people looking at us strangly..etc. By nature I think most people are just more relaxed at home, in smaller settings.
Like I said, the way I handle this, is to just force myself to go to the store and concentrate on why I am there. Picture myself walking out the door(after buying what I need)and returning home and relaxing. Nothing is going to happen to you. If it was...it would have by now. Just the knowledge that it IS anxiety, is a help. You know it isnt anything that is going to kill you.