Went through this a few years ago, not an easy thing.
I'd say endorphines you get out of exercising are a big helper, also feeling proud of urself after running or going to the gym helps a lot, but u need to force yourself to go back to the gym for a few times and that's not easy.
Food I'd avoid carbs as much as possible because they have a big impact on how you feel.
Buy a brightlight and read about the lack of sun depression syndrom thing online.
Maybe you should go on the snowmobile today (given there is no snowstorm, ggghh), spend a day just for YOU and come back with enough energy to excercise and be carefull about the food. Might be enough to start going back up.
If everything fails, jump on a plane, come spend a week or two in Paris. Living with the frenchs for a whle will for sure give you a better feeling about your life, lol
And as a few other said here, I'm always online
