You know there is a reason why grad schools don't consider the GRE the sole indicator of grad school ability. Even if you scored lower once, it hardly makes you any less capable than any of your friends. Maybe you were having a bad day, or maybe the questions you got were just some really bad ones.
Grad schools look at a whole bunch of factors including your
statement of purpose and
LORs before making a decision. Why? Because the GRE is probably the worst indicator there is of intellectual ability. It is just a tool to sift the thousands of applications that they receive. In the end, the GRE is just a necessary means to an end. it has absolutely zero correlation to your intellect or abilities. Period.
So stop feeling down and get on with your work. Good luck!