What do you want from your pdoc? It often helps to have a list of thing you want to address: meds, scripts, side effects, blood tests, current mood, recent mood. Its really important to have some control over where the appointment goes but you are also there cos you want their expertise - so its a balance...
Your options depend a bit on cost and availability - can you start looking around and asking other people so that if things don't go well in October you have something ready to fall back on? (you can cancel it if you need to) Or if you think that you need help sooner, is there anyone that you can see sooner? What does you insurance/ disability allow for?