Hello, Firstly its great you've book an appointment and hopefully find the reason why you;re dizzy. They will probably check your blood pressure as that can cause dizziness too and if you are stressed because your foot pain is disrupting your day-to-day that might affect your blood pressure. With your feet, Can I ask with the itching, if you scratch it does the itch go away or does it continue to itch? I ask this because it does sound very nerve related, the pressure, tingling etc, and with nerve problems when you have an itch and scratch it, it doesn't tend to go away. My mine thing for you do to is to make sure you definitely see a doctor or your Diabetic nurse and get everything checked out.
In the link it does say about high blood pressure, and like I said ^ up there that could be why you're dizzy.
http://www.diabetes.co.uk/diabetes-complications/diabetes-neuropathy.html
This might not be much help and I am not a doctor, but I have had dizziness like this before and it was my blood pressure and being diabetic you are prone to things like high blood pressure, high high cholesterol, retinopathy etc. Let us know what happens.
Take care. xoxo