Bleak

I understand what you’re feeling, it’s the pessimistic side of oneself that tells you that some of your nightmares just might come true.

The worst part of this is that you can never be sure wheter you’re fighting it or surrendering.

If you do everything you can to avoid becoming the gloomy vision of your future self then you’ll simply become a slave of your fear, driven by the thought, but never free from it.
And if you choose to accept that you might end up this way, maybe hoping that the thought will go away with acceptance, you have to fear to completely give in to it.

Both ways are hard to deal with mentally, both ways are flawed and might lead you just to the point you were afraid of.
But i also think both ways can, if you’re lucky or something, lead to overcoming this.

As a kid i always told myself that i hoped i won’t become a beggar, freezing in the night, starving during the day. That ‘gee, I hope this doesn’t happen’ did brand the thought that it just might happen into my mind.
But instead of trying to fight it and doing something to avoid it i started imagining myself in that role, sometimes even roleplaying it, while everytime i thought about this, the vision of myself starving in the streets became less forgettable, less removeable and for me, more and more likely to happen.
So i accepted it.
Funny thing is, the moment i told my childish mind that this will eventually happen, it became less of a nightmare and more like an unpleasant yet unavoidable docor’s appointment. Still wasn’t gone, still wasn’t (and isn’t) pleasant to think about it, but it doesn’t feel like its consuming my mind anymore.

I hope this helps you find a way to deal with your feeling/fear of you possibly becoming lonely someday.