Hi Mary and welcome from me too.
Thrush is common with high blood glucose (BG) levels caused by diabetes because your kidneys try to remove the excess glucose through your urine and the high sugar content is an ideal environment for a yeast infection to thrive. So if it is genital itching then Canesten can be purchased from most large supermarkets or pharmacies. If it is general itching, it could be dry skin, due to the kidneys working overtime.... especially if you have had the classic symptoms of thirst and resultant frequent weeing.
Drinking plenty of plain water will help to flush the excess glucose out of your system as well as rehydrate you but it is also important to put less glucose into your blood in the first place and the way to do this is to reduce the amount of carbohydrates you eat. Carbohydrates are sugars and the more complex starchy foods. So whilst you may already know to cut down on added sugar and cakes and biscuits and sweets and puddings, you may not be so aware that fruit and fruit juice particularly can be a problem, so restrict yourself to just one piece of fruit a day and best to steer clear of the more exotic ones like bananas, pineapple and mango which are higher in carbs. Many of us tend to have berries or at the moment I am having stewed rhubarb with a little sweetener as my daily portion in my morning yoghurt. If you thing of the more tart fruits, they will be lowest in sugar and a small amount packs a big punch flavour wise as well as being nutrient dense.
Starchy carbs are foods made from grains like bread, pasta, rice, couscous, breakfast cereals, pastry, batter, and root veg like potatoes and parsnips and sweet potatoes are also quite high carb. That's not to say you can't have any of these things but look at halving your normal portion size as a start and bulking out your plate with more green leafy veg like cabbage, kale, spinach, brussel sprouts, broccoli and cauliflower. Also Mediterranean veg like courgettes and aubergines and peppers and tomatoes and onions and garlic... I love a big pan of ratatouille with some quality beef burgers or high meat content sausages or lamb chops or chicken.
Getting out and getting some gentle daily exercise like a walk is also really helpful if you are able as your muscles will use up their glucose stores and draw more out of your blood stream, also helping to reduce your BG levels .
Anyway, just thinking that you could start making some lifestyle changes now in advance of seeing the nurse, since your appointment is quite a way hence, which might improve your itching symptoms if they are diabetes related.