I have no evidence, no medical studies to show that this is so, but I have no doubts either. I believe that to get out of depression, tiredness, fatigue, and all that shit, first you have to work on the body, since a healthy body means a healthy mind, for this it is good to do a sport, no matter what it is with such that it keeps our body busy. Another important factor is studying, it doesn't really matter what, it doesn't matter if it's for university, school, or for yourself, you have to do it in order to keep your mind occupied in something productive. I would also say that looking for a job, or generating income with an enterprise, since this will keep our minds and bodies busy, while giving us money, in itself gives us a reason to move forward.
Another important point is to stop comparing yourself with others, stop thinking that the other is better than you because you have more knowledge, money, or physical condition. Besides, it is very silly to think about issues such as superiority or inferiority, we are all human, we all have problems and difficulties in life, of course there are degrees of this, but this does not have to be a limitation. You have to focus on yourself, on your problems, on your virtues, on your life, and not on that of others.
Another issue is guilt, and remorse, which depending on the person can be the easiest part, or difficult to overcome, because it is easy to forgive others, but sometimes it is difficult, if not impossible, to forgive oneself. No matter how dirty your hands are, they can always be cleaned. You have to accept your sins, accept what you did wrong, and live with it. Going to a priest, a psychologist, or telling someone you trust what you did, this can help, it doesn't matter if you think psychology is a joke, or if you don't believe in God, the important thing is to get out somehow the weight you are carrying.
My least favorite part of this thread is going to a psychiatrist, and being prescribed drugs, which in itself sucks. But these in some cases are necessary to be able to do the above. Non-magical drugs, and you can't expect them to solve all your problems, but they are an excellent complement to do some of the steps mentioned in this thread.