If we lost our salvation every time we sinned, then no one would ever be saved -- because no matter how hard we try, even as Christians we still sin. The Bible says, "If we claim to be without sin, we deceive ourselves and the truth is not in us" (1 John 1:8).
But when Jesus Christ died on the cross, He took away all our sins -- past, present, and future! As the perfect Son of God, He was without sin, but on the cross every sin we ever committed -- and ever would commit -- was laid on Him, and He paid the penalty for them all. Because of what He did for us, when we come to Him by faith, God forgives all our sins -- completely and fully. The Bible's promise is true: "Therefore, there is now no condemnation for those who are in Christ Jesus" (Romans 8:1).
Does this mean we don't need to worry if we sin, or that we can live any way we want to since our sins are now forgiven? No, it doesn't. Sin is an offense to God, and when we sin, it cuts us off from His fellowship. More than that, it hurts our witness and makes others doubt if the Gospel is true. When you sin, immediately confess it to God and seek His forgiveness.
God loves you; He loves you so much that His Son was willing to give His life for you. Let that truth sink deeply into your soul -- and ask God to help you love Him in return.