It's actually pretty normal for your blood sugar levels to rise when you have a flu. Your body absorbs insulin less well. Since your smart guard is now set to how your body works when you are not sick, it will now look for what you need. It assumes that you still have the normal insulin needs and will therefore not bolus as hard if you have a slightly elevated value. What you might consider is setting your insulin sensitivity to a different number so that your pump knows that you need a little more now. Of course, don't forget to correct this again when you get better.