Your writing may come from you, it may be a product of your mind, but your writing is not you. And it bears no reflection on your value as a person.
The number of books, poems or screenplays you've written, the amount of traffic you get on your blog--none of these things is a measure of you as person.
Your writing may be good or bad, and others may judge your writing good or bad, but neither your writing nor the judgment of others is a measure of you.
Just keep writing, and keep improving. Don't give up. That's how you should measure yourself.