The two quotations relate to multiple themes in the book. Ishmael Beah relates his time and experience as a child soldier during Sierra Leone's brutal civil war. As a child caught up in a war and then forced to fight, he cannot fully understand what is happening, so there is both a loss of innocence, which we associate with childhood, and a fatalism about the war: will it ever end? He has no way of knowing, which is terrifying, all the more so because of his youth and isolation.
At the end of the first quotation, he thinks of some of his companions. The war has ripped apart families, communities, and villages, leaving Beah and other children cut off from much of what makes us human. The effect is isolating and alienating. He is a stranger in his own land, thrown in with older soldiers whose only concern for him is that he fight for a cause that he is only dimly aware of. So along with his solitude, the war is also stripping away his individuality and personality, which puts him even more on the outside of what is happening. This is clear in the second quotation from the book, in which the war has taken everything from him. Part of his purpose in writing the book is to reclaim these things.