Speaking from personal experience the uncontrollable irritability we experience as a SAD symptom is one of the worse because you feel so guilty once you calm down at having snapped at your children (i have 3 boys).
I can tell you that my SAD symptoms are a lot better this year than they have been for the last 2 years where anxiety, social withdrawal and irritability were particularly high.
If you are not currently on any prescription medication i would urge you to look into nutritional food supplements to help with your symptoms. I believe my improvement have come as a direct result of visiting a nutritionist earlier in the year and following a healthy diet in conjunction with Vitamin D supplements and l-trytophan ( the only supplement that converts directly to serotonin in the body) all with no nasty side effects associated with AD's.
I would recommend getting as much fresh air as possible as well, last year i always felt better taking my youngest to the park in the when possible (that made him happy and was good for me too being in the fresh air!!!)
Good luck in whatever you decide, post again with more details in what you are doing to minimise the SAD effects or PM me if you prefer and i will reply.