He does not realize that other people are too busy and too much interested in themselves and other things to devote to him any of their time beyond what is absolutely necessary.

When he thinks they are aiming remarks at him, putting slights upon him, or trying to hold him up to the ridicule of others, they may not be even conscious of his presence.
Morbid sensitiveness requires heroic treatment.

A sufferer who wishes to overcome it must take himself in hand as determinedly as he would if he wished to get control of a quick temper, or to rid himself of a habit of lying, or stealing, or drinking, or any other defect which prevented his being a whole man.
"What shall I do to get rid of it ?" asks a victim.

Think less of yourself and more of others.

Mingle freely with people.