When looking at why we feel the way we do, we have to first take a look at our thought process.

Sometimes the thoughts that come into our minds the most are the ones that are not very nice to ourselves. Ex. "I'm such an idiot", "Why did I trust that person?", etc.. There’s always a reason from your past to think these thoughts. For example, If you have told yourself horrible things are going to happen or people are going to talk about you or that people are going to keep doing things to you or that you are ugly or fat or not normal or everyone is happier or nobody loves you, there's a reason. All thoughts about yourself come from somewhere in your past. Did anyone ever call you an idiot or refer to someone else as an idiot in your presence.
Did you know that shaming yourself actually releases dopamine from the same part of your brain as when you are proud of yourself?
Did you know that shaming yourself actually releases dopamine from the same part of your brain as when you are proud of yourself?