When I was young, I thought I'd be dead by 18.
Then when I was still alive and kicking at 19, I thought I'd be dead by 25. Then 30.
Now I'm starting to think I'll be alive until I die from something other than suicide even though I don't want to be.
I could never see a future that was tangible, in reach and meaningful. I mostly just coast along day to day with little real purpose/goal and I think I've been like that my whole life. Largely on autopilot. Which is quite sad and pointless.
But then there was the brief interlude where I actually did see a meaningful future, in large part to the synchronicity between my fiancé and I. It was actually very odd for me - an alien feeling - to be "happy", to actually look forward to building something.
(I've had plenty relationships before him where I didn't feel this way, something about us together just fit).
Anyway it was short lived because of his death. His death reset me to how I was before I met him but magnified tenfold. I am absolutely incapable of envisioning any kind of future where anything at all is worth it anymore, never mind trying to attain it. Yet, I'm still here.
Right now there are probably millions of humans out there living a monotonous life that they're not particularly attached to. But they go through the motions of what society dictates, they survive, but they don't question if it's worth it: autopilot. Only reason I suspect they don't find their way here is because they haven't started questioning if it's worth it.
Also, I'm two decades older than you and I still don't feel like a "real adult".