large rise in blood sugar after breakfast

Hi all I'm T2 on Metformin and for quite some time now within an hour of having a small breakfast (shreddies or cornflakes with little milk) my glucose levels shoot up to around 15mmol/ml, They do come back down but I feel it's keeping my HbA1c reading a tad high. Has anyone had something...

Good morning to you all, Can you help me with odd blood reading. I'm type 2 for 17 years I take Metformin, humulin at bedtime and Victoza of a morning. I have recently had several instances when my blood 1st thing on a morning is as low as 5 but after have breakfast of weetabix or rice krispies...