Be The Protagonist
Don't complain. Don't wallow in self-pity. Don't let misfortune sap you of strength and agency. Get out of the situation that makes you the victim, and become the protagonist of your story again.
Accept that life is harsh. That the world isn't fair. That good people sometimes lose. That injustice wins too often. Accept things as they happen. As they are. That way, you won't feel so broken and lost when misfortune happens to you. They simply happen—to you and to others.
Complaining won't turn things around. But action can. You can. So get up and get to work.