No, it wasn't a cry of despair or hopelessness, as if He had decided His life was a failure. Nor did it simply mark the end of His life -- although they were His final words: "Jesus said, 'It is finished.' With that, he bowed his head and gave up his spirit" (John 19:30).
Instead, His words were a strong affirmation that the work God had given Him to do during His time on earth was now completed. Just as God finished His work of creation at the end of the sixth day, so Jesus finished His work at the end of His life. In His final prayer Jesus said to His heavenly Father, "I have brought you glory on earth by completing the work you gave me to do" (John 17:4). Nothing more needed to be done!
What was that work? Why did Jesus leave heaven's glory and come into the world? He came for one reason: to become the final sacrifice for our sins. We deserve only God's judgment because of our sins -- but on the cross, Jesus Christ took upon Himself the judgment and Hell that we deserve. He did for us what we could never do for ourselves -- and now God offers us salvation as a free gift because of Christ's death for us.
But like any other gift, we must receive it. We do this by turning to God in repentance and faith, and trusting Christ alone for our salvation. Have you received this gift into your life?