Frieda, I've had it 47 years and I still screw up on a regular basis. I still try to do my best to count carbs and bolus for them. if I underestimate, I correct and move on.
the nuts are a great idea. here's a popular post with other low carb snacks
https://forum.tudiabetes.org/topics/the-top-23-low-carb-snacks
I also think most of those cakes and cupcakes aren't really as good as you think they are.