Sleep as a symbol
Proust frames the memoirs by addressing his history of restlessness at night. As a child, he remembers being completely unable to sleep until his mother helped him fall asleep. The emotional journey he endures with sleep is a signal to the reader that he fights invisible battles that make him less likely to succeed, the same way a sleepless child is chronically prone to suffer in daily life, because they're tired. In other words, sleep is a symbol of his chronic struggle in life. He is a sufferer, ever since youth.
Women as a motif
The symbol of Proust's own mother verges on religious, and through motif, he elaborates the complicated relationship he has with women. His mother helps him sleep, and after the death of his father, he has his first encounter with sexuality, but it isn't between a man and a woman—it is between a woman and a woman. He remembers the synchronicity between that instance and his struggle to feel included in the sexual dynamic, which is a theme of the book.
Marriage and social regard
Through marriage, people can improve or worsen their regard in their community, especially during Proust's time where that aspect of marriage was thoroughly and openly discussed. Therefore, the prospect of marriage is literally a symbol in his life of his own worth. Marriage makes him address his rank in a social hierarchy, which just underscores his journey toward self-esteem. Those with high self-esteems come into marriage more likely to succeed, but with his suffering, he doesn't feel he will impress the lady folk.
Bloch as a symbol
Proust is regarded as one of the most important writers of his time, and he continues to be a major influence, especially in the memoir genre, even today. That makes Bloch an especially significant part of the book, because it is to Proust what Proust became to many writers—an artistic and philosophical influence. The symbol is an archetypal one, because Proust's development as a writer was heralded by his discovery of his artistic forefather, so to speak.
The archetypal quest of memory
Proust desires to remember what happened to him, which is an archetypal journey into his own past. It is archetypal because he doesn't remember everything, as the title suggests (much of his Time has been Lost). Therefore, he remembers the events that shaped him. His memory is a log of all the sources of the emotions he carries with him in daily life, their origin, and by explaining his memories to the reader, he invites the reader to contemplate the idea of Proust as the heroic protagonist.