Work and Anxiety

I used to work at PINK. I loved the atmosphere and my coworkers. They were so uplifting and they were beautiful women to work with. However, I always felt really shy and my heart would start pounding if a customer would come up to me. I’d do my best to help them and make sure that they left the store satisfied. Idk why working in retail gives me anxiety. When I’m walking in the neighborhood I’m fine. If someone comes up to me in the street, I’m fine. I want to get back to work... preferably at PINK because it’s the best retail job I’ve ever had. I just want to get over the anxiety. I’m not sure why this happens.