I used to be in the same boat and realized I had to go to the basic and build up from that point. I bought a book that provided a good review of basic math and started feeling confident enough to review and attack Kaplan Math Workbook and then I realized I still needed help with word problems. Therefore, I bought the MGMAT Word Problems book and work on my weakness...
At some point, I believe that my new improved technique has helped me along the way and after 4 months of serious studying, I am now looking forward to take the test.
My advice to you would be to take your time and learn from your mistakes. During my first prep, back 2 years ago, I rushed everything because my wife was pregnant and thought I would never have enough time to commit to studying afterward. However, I learned to prioritize and make some real concessions so I can get admitted in a good Business School and even with two young babies at home, I feel stronger than ever! Do not rush anything, give yourself some time to build a solid foundation of the concepts tested in the GMAT, prioritize, visualize, and most important of all... HAVE FUN!
Cheers!