Hi Lospollos,
I'll begin with an apology for the length of this, but I think it's important to really think this through carefully.
Reading other people's responses disturbs me a little. I know people mean well but I'm not sure anyone can or should tell you "do" or "don't". We're all here because we're considering ending our own lives for our own reasons but that doesn't mean we all will. Clearly there are people who have been here on the forum for a considerable time, and that's their right. Just because someone is feeling suicidal, or even planning suicide, doesn't necessarily mean they will commit suicide or even that they really want to. These are very complex issues that other people can help you think about, but ultimately can only be resolved by you.
The impulse to reach out to the teacher indicates that maybe what you really want more than anything is someone you respect to acknowledge the pain you're struggling with. That's a good and healthy impulse. People are correct to advise you that the teacher has no discretion in the matter and must report that she believes you are at risk. It's possible that the interventions that follow will provide the support you need and offer you other possibilities than taking your own life. I don't think anyone should try to discount that opportunity for you. The outcome may not be the solution to your problems, but you'll never know if you don't try.
If you have the impulse to trust the teacher then it might be worth talking to her. Even if it doesn't ultimately prove to be helpful, it's not like they're going to straight-jacket you and throw you in a psych ward...they'll bring in people to help with the kinds of pain and anxiety you're struggling with. I wish for you, and for me and for everyone here that a living solution would displace the terminal solution we're all considering. It may not occur for many of us, but I feel we should celebrate the outcome for those who do.
Good luck, whatever you decide Lospollos.
p.s. I am myself a secondary teacher and I'm willing to discuss the matter with you one to one if you like (my kik account name is: omw2ctb)