That actually sounds more like hypoglycemia (low blood sugar
) than diabetes. Do you get "sick" a long time after you eat the sweet, or immediately?
If it's a long time, it sounds like your blood sugar may be dipping low after spiking, and that feels really awful. You might get shaky, kind of panicky, clammy, etc.
You should mention it to your doc - and maybe in the meantime, limit your sweets like you've been doing seems like a very good plan.