Ok, I'm glad you were able to see her. You do need to be your own health advocate. It's absurd that a doctor isn't "available" for three weeks. All doctors have responsibilities to their patients. If they are sick or on vacation, there must be another doctor covering for them. Do not accept any excuse from the reception desk or the nurse that no one can help you. No medical practice works that way, a doctor not available for three weeks. I'd be looking for another doctor.
Any adjustment to your diet, the food you're eating, may affect your meds, so don't forget that if you do suddenly eliminate some food you were eating before, then your meds may bring down your blood sugar too low and they would have to be adjusted again. I am not on insulin so I don't know if that adjustment can only be made on the doctor's end of if the patient can initiate it. Just be aware that if your insulin dosage is based on one particular way of eating and you change it, then you might see lows.
It may take awhile for the blood sugar to even out, though, especially with the change of food as well as meds dosage. This is why keeping a daily log is so important. For each day, write fasting BS and time, breakfast time and what you eat and BS before and after and so on throughout the day, every day. In this way you and the doctor will see trends.
You realize how important it is to bring the blood sugar much lower than it's been. Good luck!