[wisty]

> Suddenly, new subjects became incomprehensible. The ease at which I previously absorbed new material was gone. Nothing "clicked" anymore. I'm in graduate school now and still nothing "clicks". I attend department seminars where visiting professors present their research, and it may as well be alien gibberish. I feel like I'm just faking my way through grad school at this point. I can still manage A's and B's in classes without ever understanding the content only because of the way the grading system's designed. Luckily, I seemed to have retained my programming capabilities.

Once you've gotten past basic calculus, you can't learn as much because all the resources are poor. Sure, you can read research papers (which are written for people who already understand 90% of them), or a PhD thesis (maybe a better option, as PhD students pad them with lots of exposition to make up the page count); but they suck compared to a well-designed undergrad text. Did you learn calculus by reading a single proof, or did you do a lot of example questions? How much are you practicing the basic techniques, or are you just saying "yeah, in principle that bit's already been done ... nothing to do there".

You also sound like you are losing motivation, and suffering a bit from "impostor syndrome", both of which are very common in grad school. You need to learn when to relax, when to push yourself, and when to just keep plugging. I find that forcing myself to relax when I'm getting distracted can "reset" my ability to focus. If you find yourself reading something that's just crap (this sentence?), look away from the monitor for as long as you can.