Dear Mike,
I'm very glad you can ask me for help.In fact,i've been like you before.Don't worry about that,I can help you.
You can try to write to your headteacher to advise that you may not wear uniform once a week .He must agree with you.And you can try your best to speak to your classmates,don't be afraid.If they laugh at you ,tell them you can speak Englishi perfect one day.Believe in yourself !
I think these advice can help you.Wish you a happy school life!
Yours,
Angela