My guess is your blood sugar
cycling up and down. Unless you take blood sugar measurements throughout the day, you will not know it, as one reading only does not tell the whole story. Have you noticed any pattern with what you eat and dizzy spells? For example, if you eat protein+fat breakfast (eggs, cheese, bacon, etc) versus a carb rich one (low fat muffin), you would likely feel better with protein+fat and otherwise dizzy with carb rich meal (which causes blood sugar cycling).