Hi Ben Cross,
Welcome to HCM Forum
What you perceived is right -Certainly Something Wrong is going with your brain.
From description written by you here my expert knowledge tells that most probably you having a mental illness caused by chemical changes in your brain.This can be controllable by means of medicine and psychotherapy
Its good thing is you taken a step to know about it by posting your query on this forum.One thing you should know that people who wants to harm you can harm you at home also and they not harmed you in last 3 month so pls dont restrict yourself at home and take help of mental health professional .
As there are certain limit to help you online it will be most helpful , if you meet to nearest psychiatrist
in person-and yes,I can assure you that he will definately help you to reduce your fear,anxiety
-will give you confidence to face the people outside of your home.
If any further query you can always post on this forum.