What are the chances someone is able to do well in their early undergraduate years, but hit a rock wall the second half of their junior year? I mean I've done really well up until this semester. I've maintained highest honors, done substantial research and been published in a journal as a co-author, and even been a teaching assistant. I then started to get my hopes up of going to graduate school etc, but those hopes are fading now. My troubles started a little bit last semester with upper level mechanics, and I only managed to do well on one exam. I ended up with a B in the class because of an enormous curve due to everyone doing poorly. Now, the same thing is happening to me with E&M and QM. I'm beginning to think that I just plain can't hack it in such a difficult major. I don't mind the studying, but I study atleast twice (maybe three) as much as some classmates whom are slackers and still get the same grades as them. I do the homework alone and in a reasonable amount of time, but completely freak out on exams and draw idiotic blanks. It's extremely annoying and as if hard work no longer equals rewarding grades. I understand that most things in life worth doing are not going to be easy, but when do you know enough is enough and just plain calling it quits? If my freaking brain full? What the hell is going on? What are indications that you are good enough to keep progressing while still maintaining some form of sanity?