The way I see it, I allowed myself to care about myself, after years of self-pity.

Self-pity and self-aggrandizement are two sides of the same coins: self-absorption. People with crippling insecurities are just as obsessed with their image and with themselves as people who feel better than everyone else. In fact, both tend seem think that they are special and unique, either in their qualities or in their brokenness. It doesn't seem to me that you've broken out of that cycle of self-absorption.

Here is what pointed me to claiming you see people as sources of validation. You never describe people as separate entities, with their own story and qualities, but always in relation to you, to your problems, to how they are judging you, you, you:

a friend of mine noted that in this battle I became what I fought: a person isolated from others...

my classmate - who was a clever girl, no doubt - rejoiced in making herself look smarter than me in class.

other people, too, thought I was smart.

their approval and appreciation I cared for far more than those of the adults who did shower me in compliments

other than not accepting me into their social circles or even as much as talking to me most of the time, they also thought I was smart

a pledge for caring

I must be fit to someone's interests and expectations of me to be worthy of their appreciation, let alone love.

you have no idea what is expected of you.

there's rarely any sensible indication of what you've achieved, as people tend to stay silent about what they feel, no matter how much pain it causes.

the rumours she heard about me

Because a few persons couldn't hold up to what others truly think of them

the world will never bend to one's effortless wishes.

a few will have to go through learning about what some people really think of them.

I have to make contact with people, reach out to them, which means - risk my ego's integrity.

so do consider before you judge the closed one.

wish that more people would respond ("How pathetic, Jesus Christ!..").

I can rarely feel my own success.

One sincere sentence - "You can do this" - from an Internet stranger whom I'll probably never meet in reality will do wonders to my motivation, for for once, someone has faith in me when I have none left.

Again, this obsession with judgement

despite sounding completely ordinary to many of you reading it

Why do you claim to know how your writing sounds to us readers? Especially since you also mention being unable to relate to others. I quote

I have no idea just how different people might be: not enough data on hands.

Which one are you, a telepath, or an alien?

Ever since I realised just how selfish people around me - particularly my parents - are

Who are you referring to, other than your parents? You've mentioned friends and the groups of people you can't seem to fit in. What is selfish about them? Excluding you? Do you feel entitled to being approached spontaneously by people, when you don't approach them spontaneously yourself?

I had very few friends, and this fact made me care deeply about each and every one of them.

It seems disturbing to apply the law of supply and demand to personal relationships. Friends are no commodity. Isn't the fact that they are your friends reason enough for you to care about them, regardless of how many they are?

When the only person you can talk to daily doesn't understand stories and tales the way you do, you're only left to talk about the superficial - and you do, just to keep their company.

This is how I learned to accept the company of people I hated - just because they payed attention to me

This strikes me as dishonest, desperate and manipulative. What is so valuable about their company that you keep it despite not enjoying it?

for the first time in my life, I had control over somebody rather than being controlled.

How have you been controlled? It seems to me that what's mostly controlling you, or rather what you let control you, is people's (perceived) judgment of you. People are not judging you all the time. They have other concerns than you - themselves, for one. The truth is most people you'll meet won't give a shit about you, and will forget all about you as quickly as they noticed you - and coming to terms with this can be incredibly liberating.