An infection of any sort can raise your blood glucose levels, so try not to worry too much about it. Make sure you take in plenty of fluids (water), and you must eat - something easy, such as eggs, fish, soup - whatever you can get down that isn't going to up your BGs.
Keep an eye on your blood glucose readings, and if they keep going up don't be afraid to ask for advice. I think I'd phone NHS Direct if they got to about 15.