Start by thinking of what a great time you have skiing. Quit drinking. Alcohol a much worse depressant than weed. Think about skiing again and again and again, until you fall asleep at night.
Physical activity is key and I also find setting goals for yourself daily and accomplishing them helps lift your spirits and gets rid of that doomed feeling that often sets in.
Really one of the best things I've found to helps with anything/everything is writing, I starting a little personal memwar a while back through they eyes of a fictional character if that makes any sense. If you dont want to talk to anyone its a good way to get whats going on in your head out but not have it come across as personal since its through someone else perspective if that makes any sense. Haven't touched it in a while but in the future id like to have a goal of getting it published.
I didnt read the op or the rest of the thread but what helps me is getting out of the house and exercising, like skiing or biking or running or hiking, something that makes you feel like you accomplished something and getting your body to release endorphins. I do notice that if I dont do anything for a while though I start feeling crappy again, so I might not be a long term life long solution, but it works
Hey not trying to be condescending at all but this was a really uplifting thread. My advice is don't be afraid to seek out professional help. I STRONGLY agree with cutting out booze and drugs, and getting active and all the rest. However, sometimes you Simply do need to talk to a psychiatrist. Good luck to everyone here, you are absolutely not the only one dealing with these problems.
Find the bitch who made you depressed, slap the shit out of her. Walk out a confident man.
Or just realize lots of people are in the same boat as you, life is indeed tough, there's always suffering but it's all in the way you deal with your problems. You can't always change your surroundings but you can change what goes on internally. We have self awareness and we have self control, it's what makes us human, use it.