If you have not heard of Stoicism, then you are truly missing a valuable asset in managing your mind through conflict, hard times, and just life in general. Seneca is one of the primary historic stoics. Check out a small portion of this wisdom in the excerpt below:
“No prize fighter can go with high spirits into the strife if he has never been beaten black and blue. The only contestant who can confidently enter the lists is the man who has seen own blood, who has felt his teeth rattle beneath his opponent’s fists, who has been tripped and felt the full force of his adversary’s charge, who has been downed in body, but not in spirit, one who, as often as he falls, rises again with greater defiance than ever.” – Seneca
There are a number of free and paid books on amazon about Seneca, but if you want a modern application book on Stoicism is: The Obstacle is the way by Ryan Holiday.