There's a few reasons your blood sugar has risen, you might need more insulin with your food or your background insulin could be too high, it also depends on what you eat. If you eat protein, fat, or fibre before carbs this will stop blood glucose spikes. I always take insulin 20 mins before I eat (unless blood sugar is around 4 or 5-ish) this gives the insulin time to work and stops big blood glucose spikes. Also stress and illness can raise blood glucose levels. I hope this is of some help but your best speaking to your doctor or a DSN .