Do you enjoy being alone? A lot of us feel pressured by society to date and get married or hang out with people we don't want to, just because others do it.
It may really be that you have subconsciously decided not to pursue these things and you feel the pressure from others and what you think society expects.
I've been there plenty of times.
Why do you feel you need validation from the opposite sex? I'm not trying to sound all feminist or empowering, but you really don't need that to feel like a real or complete person.
Is it your looks, your attitude or something you feel is not good enough? If so, then waiting for others to change their opinions won't work.
You, in fact, need to change that perception of yourself first. If it's that you dress sloppy and no one will approach you, change that. If it's that you are always locked up in your room, change that. Most of these things are all your own self-perception or personal choices.
And if you are indeed happy with how you are and don't want to change for other people, that's fine, too. Just understand that they all have standards and lives that they may not be willing to change either.
People are good and people are cruel. Some will judge you, others may be inspired by you.
Stop being afraid and stop punishing yourself for being happy alone. You sound like you are letting that anxiety steal your happiness, and it all stems from something you have the power to control.