Mental Fatigue

I have been studying and preparing for the LSAT since April 2026. I feel like I peaked in August where I was getting every single drill question correct and it all started to make sense but then in September, I started regressing. I've found that I can't study for more than 30 minutes at a time now before I get distracted or my brain feels tired. I tried taking another practice test last week and couldn't finish the last section which caused me to score poorly. I sit there and read the same sentence over and over again and still have no idea what the first words were by the time I get to the end. I take the real thing on Friday and I'm worried that I pushed myself for too long. Any tips on how to decrease my mental fatigue and continue to prep in the final days?