If you fail to walk the path of self-discipline you will begin to feel lost and out-of-control, loose ambition as you lose your motivation and drive to work, and fall into a self-pitying hellscape, and finally depression(or worse).
The recipe is simple but you are the only one who can implement it.
Read and open your mind to explore ideas.
Do the hard things first.
Challenge yourself always.
Challenge your fears.
Deprive yourself of nice things.
Workout, run, ride a bike, get up and move.
Control your emotions.
Wish the best and think the best of others.
Outline a loose and adaptable plan for your daily activities.
I am sure this is the recipe to fortify your body and mind, kill depression, do better work (and more of it), and keep a high level of personal happiness in all situations.