I’m a teacher. I have the same story as you. Cutting and suicide attempt. Heck, I still think about it now and then. Here is what I know now just because I’m old and have lived through it. You have to keep going. Live another day, then another, and another. Because it’s not all bad. Some days are pretty fucking amazing. Some days suck too. Some are just eh. But if you stop living, you never get to experience any of them. It’s just game over. You don’t get to play anymore. I know some days that sounds tempting but it isn’t. You won’t know. You’ll just be powered off for eternity. And that is a waste of life experiences. As far as telling your teacher, it probably would help. The more I confessed my secret dark thoughts to others, the less powerful they became. You aren’t a freak. Lots of people think this way . They are called existentialists. Google that word, you’ll thank me. Good luck.