Hello everyone

I am 14, and have concerns for OCD, Avoidant, and Schizotypal Personality Disorder. They seem to be getting worse at the moment. I have written other posts concerning why I believe I have them. I know I have had OCD since I was 7. (There is too much info on these disorders to write here, but I already posted it all in my other posts).
I tried telling my parents all of this, but they believe I will "grow out of it" or it's "not that bad" and my mother gets mad and screams at me; "well do you want me to get you locked up?". I just can't take it anymore, why can't I be normal? There is a bad stigma surrounding mental illness and it's almost impossible to talk about it at school. All they do is teach us about physical conditions, when a lot of psychological conditions are just as bad, if not worse.
Anyway, I have had enouh. I feel tired of constant worrying and frustration, and I am in an important year at school. I want to tell school but I have no idea how. I have so much to talk about, and I don't know id they know all about Schizotypal and Avoidant etc. Should I write it all down? I've tried to talk to my parents for the past 2 years about OCD, but they won't listen. I started self harming because of the horrible images and thoughts in my head, and they still denied me help. What should I do/say? I really want to tell someone, but I don't know where to start.
Thank you, take care