My advice is to narrow down your topic as much as possible, and make it very specific. Usually people choose a topic that's just too general, and you go all over the place because the topic is too vague and you start speaking in generalities and don't have anything interesting to say. Think back about your general impressions about the book, and then try to pinpoint the specific details that gave you that impression. See if you can detect a pattern and explore the pattern in as much specific detail as possible, and how it reinforces one or more of the themes of the book. E.g. if a certain character always seems creepy, how does the author create that effect? Maybe there are always images of death involved in descriptions of that character. What role does that creepy character play in developing the themes of the novel? Get your ideas down in point form and then try to organize your argument in a very rough outline before you start writing. Then writing 5 pages will go very quickly if you know where you are going. It is totally doable to get this done by 2 pm tomorrow. Even if you only get 50%, that's only a 7.5% loss instead of 15%, and if you take the time to organize your thoughts before you start writing, you will probably do better than 50%. Just think of your genuine reactions to the book, and try to pinpoint the techniques the author used to get that response out of you. Trust me, the writer has taken care to produce these effects by using certain techniques. Pick a really tight topic, and explore it thoroughly in as much detail as possible, and you will be fine. The easiest thing is to detect a certain pattern of imagery, and show in detail how the author is using it and why.