I don't consider myself to be very good at dream analysis, but I'll share a few observations and thoughts. There certainly is an element of self-attack (shooting yourself) and then nobody seems to notice or care that you've hurt yourself except for the teacher (parent, authority figure) to pin blame on you and punish you. The cops aren't there... perhaps the authorities in your life don't care to protect or help you.
Then your dad notices that something is wrong, but merely asks if you are alright. You try to hide that you are hurt and clean up the massive wound all by yourself. You don't feel pain, or are not connected with your pain.
The Japanese student is like an innocent pacifist bystander, and you don't want her to get into trouble. Don't know exactly where she fits in terms of your life.
It sounds like your understanding of this dream and what it says about your life is pretty accurate: self-attack, rejection, hiding your pain from others and yourself, and being neglected by those in your life who were responsible for protecting and nurturing you. You are bringing some of these same expectations into your interaction with the FDR community, which is perfectly understandable. On an emotional level, you are jumping to the conclusion that a lack of attention here equals rejection and means that people don't think you are "worthy" of the conversation. Of course, you are quite young and will soon be ahead of where many of us were at the same age (if not already). Compared to the people I have met elsewhere, the people I've met at FDR have been truly amazing, and I would be very upset if I felt rejected here. It's easy to jump to conclusions based on scant evidence, especially when most of us come with so much emotional baggage from the past.
Anyway, I think you're very brave to share so much of your inner life and childhood experiences with us in these posts (and I wasn't bored by them at all). You've been vulnerable, and I agree with Stef that with vulnerability comes safety and certainty. I don't think any of us will attack you here (better not!), and if anybody does, you will know with certainty that you don't want to interact with that individual. I think that as you interact with people that don't attack or reject you, you will learn not to self-attack and to accept yourself and your full experience in life, including your pain. Thanks for sharing!