I am sorry about your dad. I think the first Coping Mechanism is to reach out, which you have done here. Attending a Mood Disorder Group has really helped.
As my psychiatrist has explained, the long cold winters tend to exaggerate Depression (Seasonal Affective Disorder). My Depression is at it's worst during winter, the symptoms peaking about Christmas time when the days are the shortest. He has directed me to use light therapy. In fact, as he has prescribed it, one is covered under my health care plan. It is on order now.
As my doctor has explained, and contrary to people's belief, you don't stare into it. You simply have it next to you for a half hour while you do your usual activities (computer, read, journal, etc). I am looking forward to this. My depression is minimal now but I don't want to slip back into the severity it has been in the past.
And yes, getting out, exercising, and eating which they tell you to do seem like the hardest things to do in your life. I simply find it impossible. Thank goodness for the group. We sometimes go for a walk together after our meetings. It is a start.