Sometimes when we are new to exercise, our body does interesting things to maintain the status quo because change in and of itself is considered bad by the body. Like water, our body has it's own understanding of level. Often times excess sugar is the blood is stored in the liver, where it remains until your body is low on sugar and your liver then coverts the stored sugar into sugar and releases it into the body. All diabetics are familiar with the dawn effect. Think of that, then imagine exercise being the trigger for that release of sugar into the blood.
Insulin is what helps your cells digest sugar for energy. In type two diabetics your insulin does not work as efficiently in the process. When you exercise you are creating a natural situation whereby your cells need the sugar and the insulin can be more effective. As your cells use the sugar in your blood, your liver starts to convert the stored sugar to maintain your high blood sugar level.
This happens for a while for two different reasons. The first is that your body needs to adjust to the demands of exercise and the new rigors of managing blood sugar levels. When you exercise you help your body use insulin more efficiently. Think of that as tuning an engine. It is kind of like changing the rotor, wire and plugs. The second reason this happens is most diabetics have problems with liver function because they develop fatty liver, a disease whereby your healthy liver cells turn to fat. In this state the liver does not store sugar well and it is more likely to convert stored sugar when not needed. As you exercise (and omega 3 helps here) and get your blood sugar under control, your liver will actually regenerate and store sugar more efficiently. If you have fatty liver and don't act to take care of yourself, it can lead to cirrhosis.
Personally I had fatty liver disease for over 14 years. The condition is now starting to be recognized as a precursor to diabetes. In the past two months my hepatic numbers have all normalized and my doctor is pretty sure my fatty liver has almost completely reversed itself. When I exercise I am far less likely to see jumps in my blood glucose levels because my sugar storage mechanism is health. I hope this explanation helps. You should google "dawn phenomenon" to learn more about this process. Once you understand that, everything else starts to make sense.