For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
Michael's answer is _so well written and points out much more than how to deal with rejection. It should be read by _every Christian every morning to remind us to live the life we have in Christ Jesus!
We aren't just 'sinners saved by grace',we are children of the Living God!
We need to believe what the Bible says about us and stop letting our emotions get in the way of living our lives as God intends.
Emotions are subjective and only tell us how we feel at any moment and they shouldn't be allowed to keep us from walking with Jesus (model our lives after Him) and listen to and _believe the guidance of the Holy Spirit who lives with us and in us.
God isn't a courtroom judge waiting with gavel raised to condemn us every time we make a mistake. He is like the father in the story of the 'prodigal son' in Luke 15:11-32. God rejoices in our salvation and loves us _way more than the father in the parable. We were lost and now we are found!
We act in ways that are consistent with what we believe about ourselves so if we think we are really sinners we will act that way but, the truth is, we are new creatures in Christ, 2 Corinthians 5:17 "Therefore, if anyone is in Christ, he is a _new creature; the old things passed away; behold, new things have come."
Galatians 2:20 says " I have been crucified with Christ and I no longer live but Christ lives in me. The life I now live in the body, I live by faith in the Son of God, who loved me and gave Himself for me."
Like Michael said, we need to appropriate the truths in the Bible about who we are and _believe them. We need to live triumphantly by walking with Jesus in the grace of God!