I am so proud of you that you have tried this one more thing before losing strength, here you can share and purge and dump what ever you need to get off your chest, it is safe and we are here to support you.
I hear what you are saying about feeling like you are at the bottom of a dark pit, well you are not alone and we are here, even if it is with a small torch to make the darkness not so dark.
I am also proud that you have talked to people, sometimes people don't know what to say or to do, and that is fine too, as long as you keep talking and keep reaching out until you find someone who will walk with you on your journey. I am wondering if you can reach out to the school or to a learning mentor or someone who you can let know that you are feeling overwhelmed and that the school work is piling up, that is it too much to think about and to manage and see if they can support you in this, you are not alone in feeling like this and I am sure that your school will be able to accommodate a plan for you to help you with this work.
So now it is time for you, for you to fill up your cup and make you the priority. I hear you say that you can't escape the people you said you would help. Maybe a note to them when they do reach out to say "hey, I am sorry you are not feeling great today, can I get back to you when I am feeling up to it myself?" You have acknowledged them and it is a polite and courteous note and if they are really struggling you can maybe direct them to Kids Helpline or to a support service to reach out to a professional, even here if they too need to chat to get some support and let off steam.
You don't need to know who you are and have it all figured out today, or even tomorrow. Take some time to just let off some steam and to keep reaching out to get some support. Sophie_M has mentioned Kids Helpline also and they have a web based support service if you feel more comfortable to type that to talk, I will put the link here for you:
Just note that the wait times may be somewhat long, which is also lets you know how many people are reaching out and that you are most certainly not alone in how you are feeling right now.
I hope to chat to you some more, if you want to. You matter so much and I would like to listen and to sit with you through this time.
Hugs to you