I feel horrible during my free time/Ex-NEET perspective

In truth I question if I should even post this here, but I was a NEET for 10+ years cumulatively, and I haven't even been working my current job for especially long (about a month). I suppose it might serve as a counterpoint to the idea that having endless free time is "living the dream" or something, as now I'm at the point in which I can barely tolerate a day off work, and feeling miserable while NEET is largely what motivated me to work again in the first place. In my experience being NEET was alright (even relieving relative to the shit that made me isolate myself) for the first few years when I could still become wholly immersed in escapism, when I didn't have to think about my life, all while I was still very young and I had some sort of vague although slight hope for the future. Now all of that is pretty much gone. Last weekend I was literally crying at a couple of different points.

It's difficult to explain exactly why, although there is a lot of obvious stuff. Aside from my mom, everyone I care about irl is gone. I think about all the mistakes and wasted time since I was a teenager really and I just feel horrible about it. And it's not as if I can look to the future instead, as I have nothing to look forward to, besides my mom eventually dying too. I don't have a single irl friend, never had a girlfriend in my life, I have no credentials, I'm in my 30s, and I can barely relate to anyone. I wouldn't go so far as to say that I enjoy my manual labor job, at least not usually quite to that point, but it's a lot less bad than the alternative for me. At least it forces me to do something other than sit around rotting in my room thinking about how horrible everything is, while usually being unable to even enjoy games, anime, and whatever else.

And I guess more to the actual point, if your NEET situation has anything at all in common with my own NEET years, you might eventually reach a state in which you can't even tolerate the self-isolation anymore, but you might not have any sort of life that could realistically be rebuilt anyway. That's the thing, this isn't a motivating™ post, I have nothing to gloat about. Don't be me. Assuming it exists, the window for recovery is definitely finite, like everything in this life is, especially depending upon what recovery is supposed to look like. You might be able to stop totally isolating yourself, get a job (if you can find an employer even wiling to hire you), but what you probably can't do is magically be able to make up for over a decade of missed social development. And mind you, I'd already tried back in my mid 20s when I was trying to turn my life around. It didn't work, at best I got pity from people. If you're different or some sort of social pariah it will be painfully obvious, and depending upon what the causes of this were, it might follow you forever.

Idk, but I think some of this is probably common to everyone, in respect to getting older. The difference is that loss and grief can be counterbalanced by growth. I have nothing of the sort, which is largely why all of my unstructured time is dominated by extreme sadness and longing.