Solid advice from mammo. Run as fast as you can from this looney nurse. Anyone who says not to test is ignorant about diabetes control and management. Her title says it all "Practice". Find a diabetes nurse or better yet an Endocrinologist, a doctor who specializes in diabetes care. He/she can refer a diabetes nurse to you. Keep trying until you find one that listens to you and cares about your well being.
Your 6.7 mmol/l is considered prediabetes; 7.0 enters diabetes land; 10.6 is high and 14.0 is dangerous. Try to avoid bad carbohydrates as they turn into sugar after digestion. Avoid things made with white flour -bread, muffins, etc - potatoes, white rice. Maintain proper body weight and do some sort of exercise daily. These all help to lower blood glucose levels.
There is no harm in testing and you need to do this! Can you see someone else for your care? Have you addressed your high BP? Don't allow someone to make you feel bad for trying to stay on top of things, she's the one being negligent! Your cardiologist can address your BP, and in the meantime try to find someone who is on your side with keeping you healthy, this nurse isn't and it appears that you are bothering her. Don't give up, stay strong and keep fighting. I wish you all the best and stay vigilant with your health! Take care.