GMAT is a computer adoptive test, and therefore it's not a matter of number of questions you got right but rather at what difficulty lelvel you started making mistakes. E.g., you could get all of the 400 level questions right but every time a program bumped up the level to say 500, you would pick the wrong answer. So GMAT kept giving you questions at 400 level, hence the low score.
Study more, buy more verbal books, and practice! You will succeed!