Jesus overcame the world by living a perfect life, without sin. He then died on the cross to pay for the sins that we have committed. On account of Jesus' perfect life and death God forgives sins. This means that Jesus is our Saviour from sin. Through faith in Jesus as our Savior we are children of God and heirs of the blessings which God has prepared for us.
All people experience grief.
Try to understand the resulting feelings and seek the needed help. Do not forget about Christ and His Church. There you can find the best help of all. God has Answers.