In the Feb exam they threw a lot of graph questions in, 2 or 3 more than usual and I think it just threw a lot of people out - me included, though I did manage to scrape it.
As MWL says, keep going over the questions again and again (regardless of what a lot of people on here say, its a method that'll pass the exams) and you will definitely see them in the exam and you won't have a problem.