Good question , you can exist but I think what you mean is your existence is acknowledged by othersSometimes I'm questioning my own sanity. As if the people around me weren't real of that my behaviour isn't actually mine but a facsimile of how people wants to perceive me.
Technically, are you someone because of yourself or because others are looking at you? Someone can exist only if there are other to witness them or else they don't.
I know that there's cogito ergo sum but in the same way if a tree falls in a forest without anyone to hear it then it doesn't make a sound.