Tim Keller blogs here some great advice on how to handle criticism...
'The biggest danger of receiving criticism is not to your reputation, but to your heart. You feel the injustice of it and feel sorry for yourself, and it tempts you to despise not only the critic, but the entire group of people from which they come.'
'...you should look to see if there is a kernel of truth in even the most exaggerated and unfair broadsides. There is usually such a kernel when the criticism comes from friends, and there is often such truth when the disapproval comes from people who actually know you.'