Ugh, it's so hard not to let the criticism take over and echo in your mind. It genuinely takes work and practice to find a balance between obsessing over negative feedback and tuning it out entirely (when some, as you say, may actually be constructive). You're right that the extent to which we absorb negative comments is often a reflection of our own insecurities. I think the best way to tackle it is to work on your self love and your own confidence in your work, and allowing yourself the latitude to mess up every once in a while, or make things that are slightly lower than your own standards.