Meditation sometimes helps when I'm really stressed try looking it up on Youtube. There are a lot of people doing guided meditation.
I understand wantting to do well in school and being worried about your mom. The same thing happened to me and I had to ask for help with classes or I wouldn't have made it. I know it's hard because you are used to understanding things right away but your teacher will apreciate you more as a student if you show that you are honestly trying. I have gotten higher grades on tough classes because the teacher knew I was trying. Unfortunately this might not be the only hard class you get so the sooner you try to accept help from others the better. As far as your mom. there isn't much you can do. Just be there for her but don't forget yourself and realize she gets to decide her life. I know it's easyer said than done and I still struggle with it too
I understand what you say about the difficulties in getting help for your depression. I have those same problems and I've been depressed for 5 years. As far as I can see I will not be getting better on my own. I found that at my county hospital they will give free services to people if they can't pay. You might want to look into your county hospital. They won't say it right out but they might tell you something if you call or go in. I don't know what they will say because you're under 18 but you can try.
I know it's easy to think that you don't want to burden your family and I'm sorry to say it's what is keeping me from getting help right now. So I can't say that I Know how to deal with that, but I am pretty sure that is the depression talking and the faster you get help the easyer it might be to make that voice to shut up and let you get better. I know feeling hopless, helpless, and worthless has only gotten worse the longer I have had depression.
I hope this was helpful and I'm sorry you are going through this if I can help you in anyway let me know
