I'm a starting graduate student in math. Without a doubt I'm not a genius or even that smart, and that creates a serious problem: I often lose my nerve while doing research or studying other people's paper. I feel that some of those people (if not most) are just too good and I crack under the pressure to produce works of similar quality. I know the right thing to do is to be "brave" and power through and see where I end up. But this issue of "cowardice" has severely hurt my productivity. Do successful researchers have same problem or are they just totally engrossed with their work and do not care about anything else? How can I somehow be more disciplined with my emotions?