Hi Anna,
I'm sorry to hear you're struggling. It's not easy when you feel like you have no one to talk to who fully understands what you're going through, especially when it sounds like you have so much responsibility weighing on your shoulders.
Is there anyone else you might possibly reach out to besides your teacher who might be able to support you without talking to your mom about it? You might try calling a hotline or exploring one of the resources on this page, if you're not sure where to start:
https://www.healthyplace.com/other-info/resources/mental-health-hotline-numbers-and-refer…
You might also want to look and see if there are any local support groups you can attend, or even perhaps an online one (I've never participated in one, myself). Online therapy might also be an option, depending on what your financial situation is like—some platforms offer financial aid options for patients who don't have a lot of disposable income, when insurance isn't an option.
I'll also be here, if you'd like to continue this discussion here or elsewhere on the blog. Just know that you are not alone, and that there are people (including your friends, and myself) who hope you will eventually be able to find other ways besides self-harm to cope with everything you're dealing with—and some of us do, at least to some extent, understand what it's like to feel like self-harm is your only option. But please, believe me when I say it's not.
Sincerely,
Kim