Hi, sorry you have had such a difficult experience so far. Many people on here with Type 2 have had a lot of success in lowering their blood sugar numbers with adding in exercise daily and eating a low carb diet, so you are definitely in the right place.
Many foods that can make your blood sugar go up a lot are things like bread, rice, pasta, potatoes, and dairy milk (the milk you put in tea, although Dairy Milk chocolate is very sugary!).
A good way of getting more information on what affects your blood sugar is to get a blood glucose monitor and strips, and test at the first bite of food and then 2 hours later.
Some people also use a CGM - continuous glucose monitor, which shows you what is happening minute to minute and is very useful to see what foods are problematic and how different things affect you, for example, stress, and illness - I am currently higher than normal as I have a cold and can usually see it coming via the blood sugar numbers before I am sympromatic!
@Rachox has a list of the blood glucose monitors and where to get them as cheaply as possible.
This forum is really brilliant as a place to come for support and to see what other people have found works for them. I would have been lost on diagnosis completely if I had not found the forum and learned so much that could help me manage the diabetes, even though there have been a lot of stumbles on the way I feel I am now doing OK and have got my HbA1c down to 40, when it was in the 120s last year like yours.
edited to add - some diabetes drugs cannot be combined safely with very low carb diets, as Resurgam has mentioned in their post, so testing is a good idea in order to make sure you are not causing yourself issues by going too low carb.