Hi and welcome!
Are you type 1 or type 2, and what meds are you on?
What was your reading before you started to eat your meal? This matters!
Bread is one of the major carbs we have to be very careful with. Many type 2's can't manage any at all because there are too many carbs per slice, and it is carbs that raise blood sugars. It doesn't matter whether your bread is white, brown or pink. Heavily seeded bread is best but still raises levels. I can't eat granary at all. I am actually better on white bread than granary. Hovis Seed Sensations Wholemeal isn't too bad (14g carbs per slice) and there are also low carb breads such as Bergen (12g carbs per slice). Have you read the label on your bread? How many grams of carbs per slice?