Gloria's Big Problem by Sarah Stiles Bright
Gloria loves to sing, dance and act in her bedroom, but not in public. No way. Gloria's big problem makes sure of that, following her wherever she goes and constantly reminding her that she's anxious and frightened, that she's not good enough and that everyone will laugh at her. Anxious Gloria worries all the time, about everything. Until, one day, Gloria summons all her courage to try out for a community theatre production. She marches herself to the audition and her big problem marches right in behind her. She gets up on stage and her big problem takes a seat in the front row and starts to laugh at her. And then at last she yells STOP! and her big problem shrinks to a little problem and Gloria wins a part in the play.