Why was Laura sick?

Laura hears the name of the gentleman caller, and she realizes that it might be the same Jim on whom she had a crush back in high school. She tells Amanda that if it is the same Jim, she will not come to the table. The idea of facing Jim horrifies her. When the doorbell rings, a terrified Laura argues with an increasingly irate Amanda about who will answer the door. Laura finally lets the two men in but flees after being introduced to Jim. Laura is sick with embarrassment.