When you say you're hitting a wall in math, have you been able to identify which specific areas you are struggling with? I recommend some sort of tracking system to help you determine exactly what is causing you to hit a wall. The test is standardized, so there are only so many concepts it will throw at you.
If you know all the fundamental material, examine issues such as calulation accuracy, speed, and set up and see if you are messing up in those areas. I would say right off hand, you need to practice your speed. If you are not completing the test you need to begin timing yourself as you practice. I time myself for each problem. It's important to begin this now so you can begin to internalize when you are spending too much time on a question. You should also take full-length practice exams.
Most test takers will attest that quality is more important than quantity when it comes to practice questions. Doing thousands of problems without any reflection isn't going to increase learning, especially if you're just recycling the same questions over and over again. There is a ton of material out there so there's no need to do repeat questions. If you're working from the OG guide, try working on some other materials and save the OG as you get closer to exam day.