Hi Sarah and welcome!
T2 (I assume that is what you have been diagnosed as) diagnosis usually comes as a bit of a shock followed by confusion from often conflicting advice. But don’t panic, it can be managed. It does require a bit of a lifestyle change in terms of diet and discipline, but we can and will help you with that. We were all in the same boat once!
The main priority is to get blood sugars under control, and there's a lot you can do even before your appointment with the DN (the delay and lack of immediate guidance is not uncommon). This means not just cutting out sugars but significantly reducing carbohydrates as well. Carbohydrates metabolise quickly to sugar in the system (some take a little longer than others) and so for diabetics they act basically as if they were sugar. So you need to cut out starchy carbs as much as possible – bread, potatoes, pasta and rice. This may be contrary to medical profession guidance you will receive to eat carbs with every meal – this is fundamentally flawed advice rejected by most well-controlled T2s on here.
In order to learn what foods you can and cannot tolerate it is recommended that you have a test meter (not usually prescribed for T2s). With this you can measure your blood glucose (BG) levels before and after meals and see what ‘spikes’ you. Again this may be contrary to professional advice you might receive which often regards testing as pointless. But how else are you supposed to learn? Many on here use the SD Codefree system (from Amazon etc) because the strips are the most cost-effective.
For low carb foods try and go for those that have less than 10g total carbohydrate per 100g, less than 5g if you can. Ignore the ‘of which sugar’ bit, that’s irrelevant to us. You will become an avid reader of food labels! As well as carbs avoid tropical fruits including bananas which are full of sugar – for us berry fruits are best.
Try to relax and ask any questions you like.