22 y/o planning to quit job for CAT exam - suggestions?

Hey all, I'm currently working at a boutique consulting firm, which pays well (~1.3 years) but has terrible working hours. I am planning to take CAT this year (already preparing for 2-3 months). Since CAT is just 90 days away I am thinking of quitting my job or at least putting in a notice period (as it will reduce my workload and expectations from me) and focusing on CAT for the days left. I don't think l'll be able to give 100% effort to the CAT exam in my current job scenario. Also, are there any alternative suggestions from folks in the same industry or anyone, by which I can get some time off (maybe medical leave for 20-30 days) or something which will give me time to prepare without quitting?