The Rescue by Joseph Conrad

Lingard's soul was exalted by his talk with Mrs. Travers, by the strain of incertitude and by extreme fatigue. On returning on board he asked after Hassim and was told that the Rajah and his sister had gone off in their canoe promising to return before midnight. The boats sent to scout between the islets north and south of the anchorage had not come back yet. He went into his cabin and throwing himself on the couch closed his eyes thinking: "I must sleep or I shall go mad."

At times he felt an unshaken confidence in Mrs. Travers -- then he remembered her face. Next moment the face would fade, he would make an effort to hold on to the image, fail -- and then become convinced without the shadow of a doubt that he was utterly lost, unless he let all these people be wiped off the face of the earth.