Stress, alcohol, fiber in foods, fats consumed, timing of meals and snacks, exercise (and if the day ends in "y", LOL!) can all affect blood sugar levels. If you are following your food plan, doing your meds and getting your exercise you might be able to look at mood for high sugars but I would look to the first three first.
"People are like stained glass windows: They sparkle and shine when the sun's out, but when the darkness sets in, their true beauty is revealed only if there is light within."
- Elizabeth Kubler-Ross