I just passed the Civil Service Exam, but I am disappointed

I just passed the Civil Service Exam, but I'm disappointed because I feel I could have scored higher. I got 89.41% with only two days of cramming, and so much could have gone better on exam day. I forgot my water and my glasses, and we started almost an hour late because one of the test-takers in my room made a mistake filling out the seating arrangement form and had to redo it. They told us to be in the examination room at 6:30, only for us to start at 8:45. I feel very disappointed and believe I could have done better.