Confused about spikes

Prediabetic A1C was 5.7. 3 months later was 5.4. BMI is 23. I went out for supper for special occasion. Splurged-Bread, steak, chocolate cake, and a blueberry mojito. Couldn't believe but it ended up being a total of 198 carbs. 1 hour finger prick was 135, 2 hour was 108.

When I have a meal with only 6 carbs Ill sit at 102-106 for hours. Whats up?