How do I set better boundaries and preserve my self esteem when I get negative feedback on my job?

Rewire the Way You Think

I'm not sure what work you've done in the past regarding self-esteem/self-worth, but I suggest that the starting point of change be to notice how you think instead of the content of thought. May I suggest that instead of trying to validate yourself by combatting the feedback you receive or your negative thoughts, you start to think about your thinking and notice that you have thoughts. Instead of waiting until negative feedback comes your way, notice thoughts at any point in your life, now, for instance. This will get you familiar with the fact that you have them, they are not you, and you can now separate from them.  

Remember, the brain secretes thoughts like the pancreas secretes bile. Thoughts are what the brain produces to get us to act. Our actions are based on what we have learned about the world around us and ourselves in that world. Feedback can be hard to accept if we were raised in an environment where we failed to develop a solid sense of self. Think about had you had more confidence in yourself, and your abilities, the comments of others would be just that, suggestions or comments, nothing you HAVE to internalize. You, however, seem negatively affected by feedback because you may have learned that is how you evaluate yourself, by other people's thoughts of you. 

Again, notice that. Notice what your mind does when it receives feedback. Notice that you have thoughts and that they tend to be negative and beat you up because the evaluation you received-that there was something wrong, you fell short in some way, was not a good one. Your mind then tells you negative things from that information because that is how you learned to go about life. Your mind is doing the same thing it always does, and that is trying to beat you into being better. The problem is that you feel like crap and start to hate/resent work and people and fear criticism. 

What you do now is to notice you have thoughts and that these are just that, thoughts. Thoughts can be noticed, they can be helpful, and we should not try to avoid or remove them. Your mind is taking in more information than you could fathom, so you cannot control all the things your mind does. All you can do is control your reaction to the thoughts. You can feel the pain of feedback while still doing things you love. Remember, pain is not itself a "bad" thing and we should not expect to not experience pain but to find meaning in enduring it (see Viktor Frankl's Man Search for Meaning). You can acknowledge, "ouch, that hurt," and tell yourself it's ok to feel hurt. You can be your advocate to try and not remove or judge the thoughts or you for having them but to hear them and move on with life, bringing the inner monologue with you. 

The feedback will keep coming, it means you are putting yourself out there. Keep going, take the feedback with a grain of salt and check it according to what you believe about yourself. Distance from those familiar and self-defeating thoughts, and I think you will feel empowered.