Welcome to the forum and thanks for making your first post which can be hard.
You have so many issues to deal with and now wonder you feel lost and struggling at times.
Some people like your mum can find it hard that others may need help by talking to a trained person who can listen and suggest strategies that will help. There are health care plans.
Headspace is an organistaion for young people as free online support.
Headspace. For ages 12-25. They have clinics that are free as well as free online support.
I understand that making an appointment makes you anxious, I wonder would you be able to phone and talk to a trained support person at beyond Blue on 1300224636. This service offers support advice action. The service is used to people being anxious. There is also a chat line online where yo type and dont have to talk, It is available from 3pm to midnight. If you go to the right hand corner of this page you will see it.
You have made a first step by writing here and maybe by writing your post you can see things a bit differently.
I so sad when the person you trusted the most lets you down.
I can see you are trying hard to help yourself. Have you see this site
It has strategies to help you.
I am interested in how you are going, so if you feel up to post as often as you like.