Not a good day

Just had my first midterm and I'm furious!! I had just turned in my exam when I realized what a mistake I had made in one of the questions. Not even a second had passed since I had given him the answer sheet so I told him please I just remembered something can't I fix it? And that **** refused. I'm so upset because I really deserve an A in this course and the question was so lame I could kill myself for making that kind of mistake! Kill me now! Buuuh