Jaide,
I have had the same situation happen in the grocery store. I knew I had to get over it, I couldn't stop buying food. What has helped me is to make a list of what I needed, by isle. I push the cart slowly, and concentrate on the music they are playing. You can also shop at a time that the store is less busy. When my anxiety is high, the lights seem to bother my eyes. I just leave my sunglasses on while I shop. If people look at me funny, I just say to myself, maybe they think I am someone famous.
The best thing I have done for myself is to keep moving forward. I say to myself,"I feel uncomfortable now but I will be fine, the wost thing that could happen is I pass out and they would have to call the fire dept. and some hot fireman would have to give me mouth to mouth," thats not the end of the world. Then when I make it out the door, I tell myself how proud I'm of myself and I can't wait to see how easy it will be next time. Don't rush and enjoy yourself, buy yourself a treat, (like a new magazine,or some M&M's)
The more practice you have the more confident you will feel. I hope you enjoy the book. Let me know what you think of it. Shannon