Hi Belinda and welcome to the forum. Have you been diagnosed as Type 2? If so and you're not overweight, it could be that you are a different type. If you can't get to below pre-diabetic levels with diet, it may be worth that conversation with your GP.
With pre-diabetes you won't need to do anything drastic, just make a few tweaks to your diet and lifestyle. I think that a very low carb diet is < 130g of carbs, which is generally what I am on, although I do have "bad" days! You should check on ready meals for "total carbohydrate" not just "of which sugars".
A reduction in sweet stuff, plus reduction in starchy carbs such as potatoes, bread, rice and pasta should see you right. Also, if you don't exercise much, try to start walking. This is the only exercise I do but it's done the trick and probably saved me £££ in petrol as I now refuse to drive anywhere which is walkable.