PE class

This semester I choose basketball for my PE class. At the beginning, I am interested in this subject, but after the first month. I begin to cut class until yesterday I suddently think that I should stop doing this. When I attend the class, it's already the time to take the final exam. However, when I practice for the exam, I twist my ankle and I think that I can ask the teacher let me take the exam next week. However, the teacher said I have already flunked in this course because I was absent too many from this class. When I heard this, the first word in my mind is "shit", but I realize that isn't anyone's fault but my fault. I regret about what I done in this course in this semester.