If you go to the Learning Zone, the orange link at the very top of the page, there is plenty of information to help inform you about diabetes and what you can do to help yourself, including with diet.
If your surgery has not referred you, the you could try contacting a local DESMOND team on this page about taking one of their courses:
DESMOND is the N.H.S.'s education service for type 2 diabetics, and they hold education sessions where they explain diabetes, and what you should do and why. (You also get a ring binder of information to take home, so you do not have to remember everything they say). I think they offer online services now as well as the in-person sessions.
Specific information on food can be found here:
If you, or someone in your family, has type 1, type 2 or another type of diabetes, you'll know that it can sometimes be difficult to know what to eat. Start here for the key information you need to make healthy food choices for a balanced diet.
www.diabetes.org.uk
And this includes recipes which may sound fancy, but are all pretty simple to make. And if you perpare larger portions you can freeze meals so that you do not have to cook from scratch every day.
www.diabetes.org.uk
The main thing about lifestyle changes, diet and exercise, is wanting to make them. So it is a case of just trying them, and not being too hard on yourself when you do struggle. Something like starting out by just making meals from scratch on the weekends instead of a ready meal is a big step to start with.
If you are not confident about cooking, that way you can give yourself as much time as you need unlike a weekday evening when you may feel more rushed and tired. Once you get into the habit of cooking then it will be easier to start cooking at other times. Plus you might have frozen meals on weekends so you can eat something healthy you made rather than resorting to a ready meal.
When you were diagnosed you would have had a blood test called an HbA1c. This measures your average glucose level over the past three months, so is a quite reliable indicator of your normal glucose level. This then gets monitored semi-regularly to check on whether things are getting better or worse, and to decide if further treatment is needed or can be stopped.
I would assume your doctors would have wanted to check it after six months, but the whole Covid situation has delayed it until now. This will be the blood test you are being asked to do, so it will show whether your condition is worsening, and if so by how much.
But if you are on medication then that should have helped. If you were not prescribed anything then your levels may not have been too high when diagnosed. Although in both cases you should still make lifestyle changes to take control of your diabetes. You never mentioned being asked to lose weight, so I assume that is not a problem.
Tiredness is a symptom of high blood glucose, but dizziness is a symptom of it being too low. My first assumption for that would be low blood pressure, though it can have other causes. I am not sure about diabetes causing oedema, but that can be caused by high blood pressure! So I would recommend talking about your symptoms with your G.P. as they could be a sign of something else.