Too much concentration on other people! If you like yourself, you don't see/care about rejection from others and that takes care of the "problem".

No one is "scanning" you for problems, they have their own; that they are concentrating on themselves is no indication that they do not like you, what they are doing is not about you. "Perceived disapproval" are the operative words; the disapproval is usually not actual but all in one's own head and heart.

If you have one friend, one person who cares for you and loves you, you are lovable and worthy friend material. Concentrate on why that friend likes you and start believing what they say instead of calling them liars because you don't see it yourself. You don't get to judge yourself harshly because you are all you have and you are "you" and the best and only you there is and that is wonderful!