Did you say you're taking the GMAT on
Monday???
There isn't much time for you to study and prepare on new concepts at this point. If you don't feel ready and you can reschedule, you might want to delay your test date to give yourself time to study. But concepts aren't learned overnight. Study schedules vary, but if you need to learn a lot of new concepts in math, you probably want to give yourself a month or two to properly study the material and do practice problem sets, and spend time on this board as well. There are a lot of threads here with study plans.
If you absolutely must take it Monday, at this point the best thing you can do is get some sleep and prepare psychologically for the test. Make sure you're well-rested, calm and confident, and do the best you can. Remember, if the score isn't what you were hoping for, you can always retake.