Hi Tory,
Normally students score within about a +/-30 point range of their test scores' average. One test score does not say exactly where you are at; take a few of them, average them out, and that is a fairly good indicator of your level.
Also so you know, a score can dip from one exam to another even with the same amount of knowledge or the same percentage of correct/incorrect. The GMAT scoring algorithm takes many factors into account, including where you make errors, how many mistakes you commit in a row, whether you finish both sections or leave questions out, whether the last few questions of either section seemed like they were guessed at, etc. I will refer you to the following articles on scoring:
https://gmat.economist.com/blog/test-taking-skills/...
https://gmat.economist.com/blog/test-taking-skills/...
https://gmat.economist.com/blog/test-taking-skills/...
https://gmat.economist.com/blog/test-taking-skills/...
Was there anything you could put your finger on that affected you the most during the exam? How did you feel during your exam? Was there a particular question type or section that gave you a lot more trouble time-wise or level-wise? What exactly do you feel was different on the real test? Can you be more specific?
Try to get as much official practice material as you can such as the Official Verbal and Official Quant Review, or the question pack 1, previous editions of
the Official Guide for GMAT Review (12th and 13th editions are best), all from mba.com.
You may use whatever resources you want, but make sure to stick to your guns. Utilize the techniques learned; do not stray form these. Sometimes it is simply a matter of needing a bit more practice, of carefulness, and of a mix of a good test day and fortune as to what questions you will get in the exam and where you get them right.
Sincerely,
Evan