Your doctor should definitely send you to a dietician, possibly an endocrinologist too. That might not happen straight away though, some doctors take their time and just tell you to watch your diet first.

Your numbers are too high - It's not safe for your body to stay that high for any length of time. It's time for you to learn about diabetes... Start with carbohydrates, these are what raise your blood sugar. Avoid potatoes, bread, sweet foods including some fruits, and make sure you take it easy - although exercise is good for lowering blood sugar, once you're that high it's dangerous to exercise. Don't play any sports or any 'harsh' exercise until your numbers are down. A gentle stroll will be fine but no exertion.

Can you see your doctor any earlier? I don't want to worry you but it is important that you start getting onto this immediately. If you can't get an earlier appointment, at least try to avoid all fast acting carbohydrates, go easy on ALL carbohydrates, eat lots of low carb vegetables, drink lots of water, and look after yourself. You may see a reduction in your BG with those changes alone.

How long have you been testing your blood sugar for? If you've been steadily climbing over a short amount of time you could possibly have type 1. This is unlikely, but still a possibility and worth looking out for.

Chances are good you're a type 2, which means you may find good control for a while with just diet changes and some exercise, (and medication with numbers like yours). In time you may need insulin, but most people find they can go years - if not decades - without insulin if they are motivated to make the right changes. (Of course if you do find out you're a type 1, you'll need insulin straight away - don't worry it's really not as scary as it seems!)

Do note that the diet changes can be short term - you only need to keep off the carbohydrate foods until your numbers are back to normal. Once they've leveled out you can start adding a little carb and keeping an eye out for which foods are ok and which ones aren't. Those that aren't ok for you can be saved for days when you've had lots of exercise and/or eaten lower carb.

There's a lot to learn, but you'll be fine once you get the hang of it :)