The world and life are neither fair or unfair. They just exist. Sometimes our lives go well, and sometimes things don't go well, but life doesn't come with a guarantee that things will go well. How we deal with life IS up to us, though. I realize that you are going through a hard time right now, but it does sound like you are dealing with it by throwing yourself a pity party. I have some alternate suggestions.
> Exercise--this generates mood boosting endorphins, and improves your overall health.
> Eat healthier--this will also improve your health.
> Get enough sleep. Lack of sleep hurts both physical and mental health.
> Watch and read funny stuff--this generates mood boosting endorphins.
> Find ways to reduce, and where possible, eliminate things that cause negative stress in your life.
> Take up a hobby, as it will distract you from dwelling upon your problems.
> Do volunteer work. Helping others is mood boosting, and also another good way to distract yourself.
> Get involved in community activities--local theater, local government, local clubs, etc. This will help distract you.
> Go on trips to interesting places. Even day trips to local museums or other local places can help distract you.
> Take courses. You will meet new people, may learn something useful in your life, and it will help distract you.
> Take up a new full or part-time job. Again, this will distract you, and expose you to new people and experiences.
It is very important to find ways to distract your mind when you have gotten into a misery rut. I know this from personal experience. I suffer from chronic life-long depression. I find that keeping myself distracted helps, along with B vitamins, and healthier eating. I do need to exercise more and get more sleep, though, but what I am already doing has helped a lot. I was also able to greatly reduce negative stress, so I am doing a lot better now.
It's not necessary to do all the things I listed--I don't do all of them, but do give some of them a try. Good luck. 
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If a man does not keep pace with his companions, perhaps it is because he hears a different drummer.
Let him step to the music which he hears, however measured, or far away.--Henry David Thoreau