How old are you? In your first couple years of undergrad I would say alot of my peers were like this, self studying every day of the year regardless of whether or not its break, but in grad school it seems to me WAY less common, and people talk about school more like a job and value their breaks from it. If you're at the beginning of your academic career my guess is its normal, as a student in a hard program at a top uni, to not need breaks and spend lots of time, even vacations, studying, but don't be surprised if in a few years your feeling changes, and allow yourself breaks when you need it. For what its worth, my grad cohort have pretty much all taken breaks from academia work jobs, gap year, extended vacations, and all agree that had we not taken those breaks we wouldn't have been motivated enough to continue onto grad school, and would have just bachelor'd out. And this is a cohort of top people, not "brainlet ngmi"ers. i just think the perspective shift that taking a break from academia gives you is more necessary the longer you spend in academia in order to maintain top productivity