You should both stop by your local pharmacy or wherever natural supplements are available and pick up a bottle of omega-3 fatty acids (fish oil pills) which will help with the lack of vitamin D during the seasonal changes. And as a given for all depressive mood swings, you should definitely not be reclusive when it hits you (e.g. curling up into a ball under the covers), make sure you're getting an adequate amount of sunlight, keep your blinds open and the like. If you're proactive about it and take the supplements prior to and during the seasonal changes, it shouldn't be as big of a problem, if one at all
We're not so different, you and I.
"Neither shall they say, lo here! nor, lo there! For, behold, the kingdom of God is in the midst of you."~ Luke 17:21