It would be useful to know the basis for your diagnosis and you GP should provide that. I would guess it was a HbA1c test that measured your average blood glucose.
Diabetes is controllable and can even be pushed into remission by appropriate diet and exercise and also in some cases medication too.
Whatever route you take, you’ll find navigating that route is very much better if you can test your blood glucose levels and see and record how they vary with diet and exercise.
It is early days for you and there’s a lot to learn, but as is often said ‘it’s not a sprint, it’s a marathon’, so don’t get too hung up about matters and try to gain some positive feelings about the progress you are about to start to make.