This is the trick of the universe, or a trade-off if you will: being completely alone also means being completely free in terms of internal experience. If you realise that - that is the greatest gift, if you are unaware it can feel like a curse.
But in our internal state of being, in our thoughts, in our emotions and the very experience of life we are always alone. Yes we can try to express them to others some extent, but it can never be complete. In that sense we are fundamentally alone, and realising that makes the problem disappear.
Because if I'm always alone internally and nature made it so, why worry about that? The need for desperate attempts to fix it disappears and you are just fine both ways, when there are people around or when there is no one around.
we're told that we need connection, but what we seek in others is really ourselves: our meaning, our purpose, we need to matter. what we actually find in others is only the illusion of that. it works (usually) and it feels good but not necessarily for everyone and there are ways to do that all by yourself. just be nice to yourself and enjoy existence. some will contemplate you as a weirdo, but that's their conditioning kicking in. it may not be for everyone, but there's really nothing wrong with that.
i was raised in a crowded family. i had dates and got married and got kids. i have a few friends left, some family left, aquaintances, sport comrades, sporadic contact and interaction with all of them ... but i spend most of my time alone and doing my thing, and rarely get bored, days fly. sometimes i might feel empty, lonely, depressed ... well then i reach out, or just soldier on, or distract myself, i know it will pass. and i think everyone has such moments, i had them all my life, being permanently crowded just distracts you from that. all in all, looking back, i'm having the blast of my lifetime and this is how i want to live the rest of it.