Dear Karen,
I have had panic attack in mall like you sometimes in a year ago. It's very common symptoms because we tend to feel embarrassed if we fainted in the crowd. but it's all our imagination.
Watch your thoughts and you will find that thoughts seemed so real but they are just our thoughts.
Accept the thoughts will help you realise how powerful yr mind is. And, sooner or latter your mind calm down and your fear will fade away. Trust me.