Welcome back. From my own experience, it certainly doesn't help if you talk yourself down.
If you look at the GMAT, you know that the question types barely change from test to test, the format stays the same and that you have to prepare yourself sufficiently to get a good score. To a certain extent, it's like managing a project, where you have finite resources such as time, money and commitments.
As for myself, I did quite a lot of practice CATs before the actual exam, but failed to grasp the fundamentals. I ended up with a 530 (q31/v33 awa 5.5), although my practice tests averaged around 580. Since then, I have signed up to a Knewton course and plan to focus extensively on the test before my next appointment on August 30th. I also need to solve all the problems from the Official Guide (First time, I practically skipped all verbal and data sufficiency questions from the OG, which in hindsight was stupid).
Good luck and keep your spirits high.