Hi susan; yes I can totally relate to the depression and daylight savings time...I HATE it too....and it is especially tough when you are in early sobriety, alone and the holidays focus on what you are trying to stop.
all i can tell you is what works for me....get up and move...do something productive, even if it is for 5 mins....you can appreciate the little things to help you. I find visiting the gratitude threads very helpful...because as bad as things are (my long-term relationship ended last Xmas) things could be much worse.
Tomorrow is the shortest day of the year....and I treasure the extra 30 seconds of daylight that comes after that.
treat yourself kindly as you are recovering from 2 illnesses...a good diet and some vitamins certainly won't hurt you...tell your doctor what you are going through, it isn't an automatic sentance for an anti-depressant...(i've been on several and for ME, i prefer a strong dose of coffee and some exercise).
try to find something you enjoy and can focus on to take your mind off of obsessing...and there is no law that you have to decorate for Xmas...you can do what you are comfortable with...even a small plant with a few baubles is significant for a tree. you don't have to overwhelm yourself.