eat fruits and vegtables and less junk food . drink water instead of soda
and get pleanty of exrcize
in order to best control your diabetes, it will be important to closely monitor your diet and in particular not too much carbs. If you eat lots of carbs you will need lots of insulin to cover them and also be more likely to gain weight.
Most vegetables are good. Fruits are ok, but they are very sweet, so portions have to be controlled. Don't eat low fat (fat helps slow the absorption of carbs and will also help you feel satisfied, even if you are eating a bit less carbs), and eat plenty of protein.
Avoid / minimise breads, cakes, pasta, rice. These will need to be eaten in controlled portions. Soda, juices and candies and sweets will need to be restricted.
Can you see a diabetes educator? Read up on using insulin. THere is a very good book called "Using Insulin" by John Walsh. YOu can probably get it on Amazon, or at a book store. It will explain a lot and is an excellent starting point. The more you learn the more tools you will have to control this.
Having diabetes is no fun, but it can be managed ok and you can still have an excellent life!
It will take some time to learn to adjust. Be patient with yourself in the meantime while you are learning. YOu have time to get things stabilised and deal\ with the weight.