A person will act and respond according to what s/he believes to be true about themselves or their environment. By nature, we are wired to look at and respond to situations in a manner of protection. If we feel threatened, we react in such a way to protect our person, those we love, even our ego. As such, our default is to recognize the negative over the positive in nearly every situation. Generally, when we are in a place of rest, our minds replay the negative experiences of the day many times over replaying of the positive experiences of the day, and this can leave us in a dire place of vulnerability.
Changing the narrative of a vulnerable mindset requires intentional actions to fill your cup with positive thoughts and tune out the distractions. This can be accomplished by journaling, meditation, reading, and surrounding yourself with people who genuinely want to see you succeed. It will take being honest with yourself about feedback received and discovering a means to channel growth from it. Flip the switch of negative default in your mind by forcing yourself to find the positive in every situation. Doing so will lead to greater levels of confidence that you can effectively overcome future challenges.