Sounds like you need a new school/college bro!

As Petina said, talk to your school's career/guidance counselor. Speak about what you want to do and they should help in trying to find out as much helpful information for you as possible (it's what they ARE there for).

If you are not getting any help from your school/college, i would strongly consider changing your college/school. You need schools or colleges that strongly support your development, both your education and also you as a person.

Regarding the attending Japanese University for English thing. While it does sound good on paper, you have to consider a few things:
1) Japanese University is expensive. If it might be expensive in your country it will most likely be just as (if not more) expensive
2) Cost of living in Japan is one of the highest in the world.
3) Although if the University does teach English. The classes (not the content) may be conducted in Japanese. This may also go for having to deal with any administrative matters as well.

Don't take what i have said above as offence to your hopes. I just want to give you advice and information that will show you how it might actually turn out.

You need to reach out and talk to people who will support you, such as your family/friends and the appropriate people in your school/college.

I feel as though my post is a bit off topic, but i understand somewhat how you feel (i had to endure some bullying etc myself in school). But i wish you the very best for the future bro!