Try to find a tutoring program in or even outside of your school. At my school, we have a Student Support Center, where students can go if they're having troubles with certain subjects, or even if they just need someone there to stay on their back to make sure they get things done. If you don't have any programs like that around, maybe ask a friend (who understands what you're having troubles with obviously) to tutor you. And if you don't want to ask a friend, maybe even try to find someone else at school. Also, if the teacher you have isn't willing to offer help, try going to a different teacher that teaches that same area. I often go to a different teacher for math help, simply because the teacher I have now doesn't teach in a way I can learn. That's all I can think of, sorry if it's no help. Good luck though! :]