Thank you for sharing your story with the RO community. I'm sorry to hear how difficult it has been for you in terms of being bullied for many years. It must be so difficult to sit with these experiences. It is understandable you want to reach out to others who can provide some advice or share their experiences.
I'm wondering if you would be interested in visiting this thread about Bullying? You may be able to add to this conversation as well as learn from others' experiences?
Bullying can have such negative impacts that I'm sorry your teachers see it and do not do anything about it. Do you have a wellbeing person, trusted teacher, or adult you can speak to about what is happening for you? It may be difficult to talk about at first, so these video tips - Talking about Bullying may be helpful for you.
ReachOut have a series of articles about Bullying which you may find helpful to go through.
What are somethings have can help you right now? Are there things you enjoy doing in your free time which can help distract you?