Many spiritual schools or paths have their own particular mantras, a word or short phrase that one repeats constantly to keep ones mind focused on God.
The Law of Attraction for money shown in The Secret and other goals have their own mantras. I have a mantra that is very effective and practical for western minded people who do not have a firm enough belief in God or the gods or in goal setting.
“What do I really want.”
These simple few words will calm you in any time of frustration as you get grounded back into your real desire, which often is peace, happiness or balance.
We lose ourselves in the hustle of the day, the hectic activities, the many choices and desires that pull us here and there, all the while going further away from what we really want.
I suggest that you ask this question for quite some time until you get a feeling of warmth and relaxation in your heart, which will come when you find what it is that you really want.
Then keep this as your mantra at all times, especially the tough ones, and maybe, this will help calm you down and put things in perspective.