It makes sense. tomatoes are a fruit and contain naturally occurring sugars and the carb in the rest would probably have been released at differing times so would keep your sugars going up for a while.
Any illness will change your blood sugars as you are fighting with a decreased immune system. Having a reading of 10 is nothing to worry about. I struggle to control my blood sugars as I have a recurring infection and c-diff so I cant have antibiotics atm, my readings are anything between 5 and 30+