Hi Themightyknight,
The good news is that your practice exam scores show that you can score much higher than 555 on the GMAT. So, it's quite possible that you had a bad day, and with a retake, you will improve your score. However, to be safe, you should engage in topical practice to find and fix any remaining weak areas before your next attempt.
For example, let’s say that you want to practice Number Properties. You can do so by answering 50 or more questions just from Number Properties: LCM, GCF, units digit patterns, divisibility, remainders, etc.
After each problem set, thoroughly analyze your incorrect questions. For example, if you got a remainder question wrong, ask yourself why. Did you make a careless mistake? Did you not properly apply the remainder formula? Was there a concept you did not understand in the question?
By carefully analyzing your mistakes, you will be able to fix your weaknesses efficiently and, in turn, improve your GMAT quant skills. Number Properties is just one example; follow this process for all quant, verbal, and DI topics.
For some more advice, here is a great article you can check out:
How to Improve Your GMAT ScoreFeel free to reach out with any questions.