YOu did not give the title of the book, but I am "assuming" that it is Tears of a Tiger by Sharon Draper. Andy is having a hard time dealing with the death of his best friend, Robbie Washington, especially since he caused the death. HIs first stanza means that he is depressed and he cannot find his way out of it. It frightens him. The second stanza means that all his friends are still their cheerful selves, and they cannot see how troubled he is. The last stanza is the most important. He cannot see the future. That means that he cannot see himself moving forward in life. His life is at an end. He says he cannot change the past. How true! Robbie is dead, and he cannot bring him back. He cannot change the fact that he was drunk and crashed the car that killed Robbie. The present is so heavy because he cannot deal with what he has done. When he says the last lines that say he doesn't think he is going to last, he is talking about death. He cannot cope with the idea he has caused so much pain, and he cannot deal with his own pain.