Your thoughts determine your life. How do you process what is happening in your life?
Other than in a few exceptional circumstances, it is not what is happening to you that is crucial, but how you perceive things.
Things may be going great in your life, or good, or average or mediocre. However, your reality is how you are processing these circumstances.
If you perceive great things to be mediocre then your life will feel mediocre irrespective of the great circumstances. If you want to change your life, begin by changing your thoughts.