No preaching, but don't use brain dumps, seriously. They are not only a waste of money, as you can't be sure that those dumps will be exactly the same as you would face in the exam, but also 'lower' the value of certifications in general. Especially when compared with people who passed exams without such methods it seems to be quite unfair. If many people use such methods but don't understand the covered topics at all, sooner or later it will be recognized in industry that certification xy isn't good at all, as many people are certified but can't handle things they should have learned while studying.
If you have used the official courseware for studying or one of the other books available (prep guide, study guide etc.) it should be sufficient to pass.
I will take the exam at the end of Feb. as well and can somehow understand how you feel. But if you have prepared well, just go for it and it will be fine.