DoE NSW Wellbeing website is an Australian Government site specially developed for younger children to support all aspects of their wellbeing: mental health, drugs, anti-bullying, out of home care, disability and funding for wellbeing.
Please see other websites such as:
Here are a lot of other useful websites:
Sleep
Sometimes Melatonin (pdf 482 KB) is used to assist with sleeping.
Anxiety
The BRAVE Program is a free online program from the University of Queensland. It is an interactive program for the prevention and treatment of childhood and adolescent anxiety. The programs are for children and teenagers to better cope with their worries.