When the narrator's mother was alive, she was concerned about her valuable possession because there was a war. Mrs. Dorling took advantage of her insecurities and fears of the war and gave her confidence that she will look after her valuable things until the war was over. So, the narrator's mother trusted her and gave  all the precious things to Mrs. Dorling for safekeeping. She did not even know that Mrs. Dorling did not have the least intention to return those back to her after the war. So, when the narrator visited Mrs. Dorling's house, she saw all the things. The belongings of her mother brought back the memories of her dead mother in her mind and thus she felt that the whole atmosphere was oppressive. The memories seem to choke her. She did not want to recall them as it only gave her aches. She decided to forget the address of Mrs. Dorling and move forward in her life.