Contemplation or Passing Thoughts

In periods of my life I catch myself wandering aimlessly through life. Simply going about my own business without much thought or consideration. When I come to that realization I usually feel a sense of guilt, or panic. How could I go through life without deep contemplation, analyzation, and consideration? Shouldn't I spend time exploring my thoughts and questions regarding life's big mysteries? Shouldn't I bog down my mind with doubt, isn't the world a complicated mess? As the crest of that wave finally peaks, I am once again faced with the beautifuly calm and simplistic expanse of life as it is. Nothing more, nothing less. Zazen...