Hi and welcome,
Yes, an HbA1c of 48 or over is diabetes, but as your HbA1c isn't drastic you should be able to do something about it fairly quickly with a bit of effort on your part. Diet is the key, and the fewer carbohydrates you eat, the lower your glucose levels will be. All carbs convert to glucose in the body, so it makes good sense to reduce the amount you eat. Bread, potatoes, rice, pasta, cereal and flour are the worst culprits.
You will have been given a meter when you had GD. Have you still got it? If not I suggest you buy a new one and some new testing strips. This will help you formulate a diet that suits you and your body.
Why would the doctor tick you off? He isn't there to be judgmental. He is there to help you.