Let me ask you a question: Did Jesus Christ die only for good people? Did He die only for people who'd never sinned in any major way?
No, of course not. Jesus Christ didn't die just to save good people; He died on the cross to save bad people also (although in reality we are all bad, because we are all sinners in the eyes of God). Do you remember the Apostle Paul's background? At one time, he hated everything Jesus stood for, and he committed his life to killing Jesus' followers and stamping out the Christian faith.
But was Paul too terrible a sinner for God to save? Were his sins so great that God couldn't forgive them? No, not at all. In time, Paul met the living Christ -- and his life was completely changed. His sins were forgiven, completely and fully -- and from that moment on Paul knew he was saved. Later, he wrote these words: "Here is a trustworthy saying that deserves full acceptance: Christ Jesus came into the world to save sinners -- of whom I am the worst" (1 Timothy 1:15).
Don't doubt God's love for you, and don't doubt what Jesus Christ did for you on the cross. All your sins were placed on Him, and He paid the penalty for sin that you deserve. Thank Him for His great love for you, and make it your goal to live for Him every day.