It is fascinating to note how Pip narrates his last days with Joe and Biddy before he leaves. We must remember the narrative style that is employed in this excellent novel, which some argue is the best produced by Dickens. He uses first person retrospective narration, which means the story is told in the first person but by an older, maturer narrator looking back at his youthful ways and faults, and often sadly critical of his own mistakes which he was so unaware of then.
This explains Pip's feelings of uneasiness of the night of the discovery of his fortunes. Consider his feelings on this night, at the end of Chapter 18. He says: "I drew away from the window, and sat down in my one chair by the bedside, feeling it very sorrowful and strange that this first night of my bright fortunes should be the loneliest I had ever known." He goes on to comment:
I put my light out, and crept into bed; and it was an uneasy bed now, and I never slept the old sound sleep in it any more.
Clearly Pip, even in his unenlightened youthful state, is able to discern that something is wrong, even though he lacks the necessary self-reflection to see how his Great Expectations have changed him for the worst. The awkwardness of his parting and his own awareness that he should have left Joe and Biddy better marks the end of the first book, but crucially he lacks the willpower to go back and make things right:
I deliberated with an aching heart whether I would not get down when we changed horses and walk back, and have another evening at home, and a better parting.
However, Pip continues to London, leaving broken relationships (on his side) behind him. Note how the first stage ends with an allusion to Paradise Lost, which surely foreshadows the problems Pip will face with his Great Expectations:
And the mists had all solemnly risen now, and the world lay spread before me.
Leaving the innocence and safety of his home in the marshes will expose Pip to ever greater dangers of corruption that will truly affect his character for the worse.