I would think that the best place to start - if you can afford it - is a psychiatrist. Although, if you have any kind of a good talking relationship with your school counselors that would be a good starting point. Of course, your parents would be number one choice.
Have you ever been diagnosed with AD/HD? I am curious because a lot of its symptoms and effects are kind of typical of a sociopaths behavior. And since it is kind of unusual for someone of your age to have this problem (unless you have been abused), it would be the starting point for treatment. If you have any questions on ADHD possibilities, please ask or post over here -