"Thou wilt shew me the path of life: in thy presence is fulness of joy; at thy right hand there are pleasures for evermore." – Psalms 119
Life is a gift from God. Perhaps, it might be said Life is Gods greatest gift!
Certainly, life was His first gift. "And the God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became aliving soul." – Genesis 2:27
Life is good. Say that! Believe that! God intends for you to be happy. He has determined to give you life that you may enjoy a relationship with Him. The best life is a God Life! And A "God Life" is better than a "Good Life!" I realize I'm a little heavy on the exclamation points here, but these are important points!
Realize your life was given to by God. Therefor, He has a plan for you. Learning about His plan and walking in it will bring you much happiness. This is the Fulfilled Life. Yes, it is Gods will for you to live A fully filled life lacking nothing. At least nothing you need.
The best definition of a fulfilled life is "living in agreement with Gods plan for your life."
Even difficult situations and setbacks work in your favor, when you are living in agreement with Gods plan. "And we know that all things work together for good to them that love God, to them who are the called according to his purpose." – Romans 8:28
Al of Gods Provison is in His purpose. Living a fulfilled life happens when we fulfill His purpose. Even in the most general sense this is true. His purpose is for us to praise Him , love Him , and be faithful to Him. This alone brings a greater peace and joy into our life.