If you have severe symptoms and suspect you have a mental illness, or you are experiencing distress, please see your GP. I recommend that you have a double appointment (20-30 mins) so you and your GP have sufficient time to discuss your symptoms and problems, and whether you qualify for Medicare coverage under the Better Access to Mental Health Plan.
Your GP will make the initial assessment and diagnosis, and suggest a general treatment plan (e.g. CBT for OCD, or EMDR for PTSD). He/she will also register you to claim rebates from Medicare and write a referral for you to see a psychologist (e.g. me).
Due to budget cuts, the maximum is for 10 sessions per calendar year. The rebate for Medicare for Clinical psychology treatment for 50 minutes or longer (Item 80010) is $124.50.