Psychology has a lot of theories. Some of them are important, others are not. One that is important but often overlooked is that of confirmation bias.
Confirmation bias occurs when we have an opinion or thought or perception, and then we become far more likely to notice or perceive that events meet that opinion. For example, if you think that you have noticeably ugly hair that day, and every time someone looks at you and looks away, you convince yourself that they are judging your ugly hair.

It occurs in three ways:

• Selectively noticing the things that meet our belief. For example, if you believe people of the opposing political party are generally unintelligent, and you look for evidence to support that belief while ignoring all of the members of the opposing political party that are intelligent.

• Selectively noticing and interpreting things based on a belief. For example, you believe that you look scary to people, and when you walk up to someone and they move away, you attribute it to looking scary rather than them having some other place to be, while ignoring all of the people that did not move away.

• Interpreting ambiguous events as the one that meets your belief.

All of these lead to strengthening of your opinions, even when wrong, and are especially harmful when it comes to self worth. Even worse is they lead to another phenomenon known as behavioural confirmation effect, also known as “self fulfilling prophecy.” When you are convinced that people do not like your personality, you go up to people and act as though they won’t like you, leading to them not liking you, and you getting your belief confirmed.
All of these can be very damaging to your self-worth, and are a big reason that you may need hypnosis/NLP to intervene and help get your self worth back on track.