In Chapter 57 Pip is very distressed about Magwitch's death, and he is in debt and worried about the state of his affairs. As a result of the stress he has been under, Pip falls ill and, after a night of great anxiety, he finds that he can no longer even sit up in bed. He does not know whether what he thinks he has experienced, such as going downstairs to check on his boat, was real or imagined. It is in this state of almost being delusional that Pip glimpses two men before him, who turn out to be debt collectors. He then slides into a fully-delusional, feverish state in which he loses his reason entirely and confuses other identities with his own. In this exhausted state, in which he loses track of time, he imagines people are murders. It is not until his ravaging fever subsides a bit that he can make out Joe's reassuring face.
Pip is very physically ill in this chapter. He has a fever, collapses, and is in and out of consciousness. His fever is so high that he has hallucinations, seeing people from his past. He thinks he's still seeing things when he sees Joe, but Joe has come to take care of Pip during his illness. Pip feels such guilt about his treatment of Joe and Biddy. He now knows that money and social standing do not necessarily mean happiness. He also realizes that he must cherish and take care of those people who mean the most to him and who love him. He had decided to tell Joe how he felt before Joe left London, but Joe had already gone, paying Pip's debts before he left. Pip decides he must make amends with Joe and Biddy.