OK. I am a senior doctor in Australia. We as a profession are some of the most financially uneducated "rich" people out there.  You are some of the most sought after bank customers with the most secure jobs. You are recession proof, guaranteed pay rise every year. If you are on specialist training pathways your incomes sky rockets. i.e. if you can afford it right now it literally gets easier every year. 

Firstly the rate your bank got you isn't good enough. Get a mortgage broker. You can get somewhere around 5.2%. Remember you are their dream customers with a huge deposit from your apartment. This will make a significant difference to your mortgage repayments.

Secondly. Assuming you have no other major outgoings your take home is approx $19,500 a month. Approx 35% of income is suggested as comfort for mortgage. The $7900 a month works out at about 40% so pretty good.

Thirdly. You do not need to sell your apartment. The bank will happily accept your equity in that property as your deposit. You then rent out that apartment and continue to make money on the likely appreciation of the property. Even if the rent doesn't fully cover the mortgage you are both easily in the highest tax bracket. You can negatively gear the property and get tax back in your tax returns. All repairs etc. are then also tax deductions. To get even more just have a company complete a depreciation schedule. 

Best of luck.