Do we live on a series of presuppositions? Responding to The Hour of Stars

The Hour of The Star is a story about a girl in poverty named Macabea from the state of Alagoas immigrated to Rio de Janeiro and went through a series of changes. Macabea in the book was living aimlessly, poorly educated, and had no family and low self-esteem. To Macabea, she had no idea of what happiness is, and she was also afraid of having those beautiful things in life. As a result, she thought she did not deserve all the good things granted to her. This was why she took the job that was under minimum wage as a typewriter. She was also shocked and anxious when she started dating Olympico.
Growing up under a hopeless place, Macabea lived for nothing, struggled to find happiness and thought herself she was hollow. She had low self-esteem and showed pessimism. I would like to ask some questions regarding Macabea’s story. Macabea provided some counter examples regarding existentialism, as humans always live based on a series of absolute presuppositions to support their empirical experiences. When Macabea interacted with her boyfriend Olympico, he had some absolute presuppositions like people always have dreams and stories about themselves. However, Macabea always responded with that she had nothing to talk about her. Macabea had no absolute presuppositions on those series of life questions. She only had the absolute presupposition that her life was meaningless and blank, so nothing in her life worth exploring. This question worth answering through more discussions, and I am going to learn more on existentialism. I am curious if people who live under a series of absolute presuppositions but all of a sudden lost all of those, and how would people cope with life from scratch?