I will recommend three types of therapy.
COGNITIVE THERAPY. Print the following text, read it often, fold the paper to a suitable size and carry it in your pocket:
I know that there are bad people who can hurt me. I am very much afraid of them and can run away from them when necessary. But I can also fight them when needed. I don’t let them hurt me. I am not a child.
On the other hand, I also know that everyone is not bad. I don’t provoke good people against me by expecting them to be bad and by being afraid of them baselessly. I have enough sense and courage to judge people and the situation correctly so that I can decide rationally to run away, to fight, or to be neutral or friendly. I always maintain a sufficient base of courage and fear, but I never become complacent or panicky. I can make friends without being hurt by them. I am not a child.
BEHAVIOR THERAPY. This consists of acting out what you promised yourself to do in the cognitive therapy, making the whole thing look like a game:
Behave as if you were running away from a danger, saying to yourself, “I am afraid, I am afraid!”
Then stop, turn back, and start behaving as if you were fighting your enemy, saying, “I’ll crash you, now take this, etc.” like Popeye does.
Behave also like you were with a trusted friend, without being complacent. Above all, try to make friends without being hurt by them. I hope that this therapy will help you to succeed.
COMPENSATION, OR SUBSTITUTION, THERAPY. All non-organic mental, or psychological, disorders are caused by harmful failures, and the only decisive remedy is to terminate the failures and their harmful consequences. The above recommendations aim to realize this. However, the harmful effect of failures on mental, or psychological, health can be reduced by compensating it by the beneficial effect of successes in various areas of activity, as exemplified below. These can be called substitute successes, which are most useful when the realized failures or their harmful effects cannot be terminated.
Pets can compensate for the lack of human friends in some measure. Some sports such as fishing, hunting, hiking, etc. can secure success and happiness even when done alone. More commonly, music, films, photography, books, etc. can be sources of happiness which can make living meaningful and enjoyable. You must find such sources of success and happiness. Famous Japanese film director Kurosawa told in an autobiographical film made up of his dreams that he found people bad and sought happiness in nature and films.
PS. Not only failures and harms but also excessive happiness can cause psychological disorder later when it is terminated. For example, a child who experiences mistreatment after becoming used to good treatment can get hurt by that mistreatment more than a child who is always treated badly. You must look for such a factor in your case.