Welcome to the Diabetes Forum, angels3. I'm sorry you're dealing with these conditions at the same time! I am not on insulin so I cannot comment on that area of your therapy but as you said, it's not working very well, so there must be a re-evaluation of your meds for diabetes. You already know that carbohydrates will raise your blood sugar but so can illness, anxiety and some medication like steroids, so if you're on anything like prednisone, you can expect high blood sugar. Normally a doctor will prescribe diabetes meds to cover the effects of the steroids.
As for diet, I don't know how you normally eat in order to keep Crohn's under control but for diabetes, the fewer carbs you eat, the better control you'll have of your blood sugar.
It's possible that you are also insulin resistant which means the insulin can't do its job no matter how much you inject. In that case, the doctor would also prescribe metformin which helps your body use the insulin. Your blood sugar is too high and you need to have it lower. (You probably also know that high blood sugar over some time can damage your heart, kidneys, eyesight, circulation, nerve endings, etc.) It seems to me that your doctor needs to act quickly to adjust your meds so your blood sugar is actually controlled. If you are type 2, especially, you're most likely insulin resistant.
Sometimes blood sugar will rise after exercise but should only be a temporary rise and under normal conditions (when the blood sugar is controled) this is not too much of a problem. This rise is for your body to have energy for the exercise. My concern would be if your blood sugar is too high all the time anyway, then the exercise is driving it higher.
Here in the States we use a different measurement for blood sugar. Our fasting should be under 100 mg/dL, which is about 5.5 mmol/L (used in Canada and probably the rest of the known world!).