Have your gp refer him to a psychologists under the Mental Health Plan, also get referred to a pediatrician (if you don't have one) for him to be assessed. My twin boys are 27mths old and we started the assessment process when they were 18mths old due to development delays and eating, sensory and obsessive behaviour issues and they have been diagnosed with ASD so they can be diagnosed early.

We have our federal government funding now in place so they now have an OT who will be working with them and me on all aspects of their issues. Early Intervention is the key for a better outcome for your little man and your sanity. PM me if you want to ask any questions.