I, too, agree that it is good that you recognize your problems here. I think counseling is an excellent route to take. Sometimes just talking about things helps work them out; and if you don't feel you can talk to your parents or your friends, then get yourself your own personal counselor to help you along the way. You'll find that there are probably a lot of things you want to get out and talk about that is leading to these feelings of anger and obsession that you're feeling. Being in high school/college is a very difficult time to go through in life and although the answers are not always clear now, they will be later on in life.

In the meantime, I think you should cool this relationship with this girl, or just be friends for now until you work out what it is you want. It might even be you're channeling all these feelings towards your teacher because you know you can't be with her and you are confused about relationships in general right now.

Is the rest of your life going the way you would like it? Do you have anger towards other things? These are all things that a counselor could work out with you.

Let us know how you make out!!!

Remember to smile.