Can I sue my old private school?

I went to a very expensive private boarding school in Australia, and was picked on pretty much everyday, verbally and physically in school and in the boarding house for being different and fat. Its now three years later and I have lost a lot of weight due to a eating disorder, I have depression and have to take heavy anti depressants also anxiety. I also have to see the physicist about once a week. Is it possible to sue the school for ignoring the situation, because even though I would inform them they were doing it the most they would get was a slap on the wrist, no suspension or expulsion.