As a union member, you will be protected!
And, on your return to work, you should not be at risk of injuring yourself in the same way. It is never okay for an employee to be discriminated against for having been injured at work.
Under Equal Opportunity Legislation it is illegal to discriminate against a person on grounds of injury or health, or for having made a work-related complaint. An unlawful termination and can result in prosecution.
Your union will make sure that you are protected!
Source: ACTU fact sheets