Mental stamina is strength of the mind. It means pushing through the hard and accomplishing what is necessary to propel you forward.
What about those moments/days/months/years that seem as if the raincloud is following you? Can you REALLY make the decision to be happy? I've contemplated this for YEARS and have finally agreed to the truth of it. You can still find joy in the midst of hardship. You can still push through the hard and notice the good. You can still positively affect those around you with your ability to be happy in the midst of the pain.
BUT HOW? It's realizing that you have NO CONTROL over what happens around you ALL the time. It does mean that you have control over how you will react to those situations!
Will you seek counseling for PTSD?
Will you avoid certain situations/people?
Will you create boundaries surrounding your joy?
Will you take a deep breath before that stressful family gathering?
Will you decide for yourself what is best and not value the opinions of others as top priority?
Will you stand up for yourself when others try to knock you down?
Will you make the choice that no one affects your mood, YOU DO?