Here's a little story to remember the next time somebody's words of criticism of your work (whether in a formal review or an off-hand remark):
According to Nicholas Clee, writing in the (London) Times, once a Swedish writer wrote a scathing review of a crime novel called The Power of Fear, by Britt-Marie Mattsson. The problem is that although the book was listed in the publisher's catalogue, it was never actually published. Confronted with this fact, the reviewer said he "got worked up in advance about Mattsson because I detest her so very greatly." Oops.
If negative reviews get to you, make a little sign that reads,
"It's only their opinion."
And if it still bugs you, remember this critic who shot down something that never existed.