Welcome to the forums!
First, congratulations on getting so close to finishing your degree despite all the mental health challenges. I had a bad period of depression during my honours year, so I understand how hard it is to study while battling depression. In my case, I ended up dropping out of honours because I didn't want to risk any further burn-out as I was trying to work at the same time.
It sounds like you have a lot on your mind which is making coping with your depression and anxiety more challenging - your study, employment, rent - hopefully finishing your study and perhaps moving back will lighten this load a bit.
In my own experience, dropping my honours and just focussing on getting a routine after my subsequent depression and break-up, really helped me find a bit more of a stable footing where I wasn't feeling so overwhelmed by everything. It sounds like you are thinking of doing something similar by focussing on your mental and physical health.
Have you run your ideas about moving back to Brisbane with family and friends? Are they also supportive of your thoughts?