I like the title of your post, interesting. Approaching my date where I backed out most recently I was quite empty and disconnected, but as the time came closer I'd say I experienced this. One moment I can be feeling worthless and then the next actually distraught and tragic because there's no way I can possibly do the things I wanted to do, and there's no denying that each of us have unique to offer into the world if we so choose. Then I ask myself, why is it worth it though? The world doesn't actually lose out, that part is just an ego driven survival instinct I think.
The way I cope with it, even though what I create is likely worthless, is just by creating as much random crap I can in the time I have. I bought some cheapy musical instruments because I love to just play little tunes, it doesn't sound amazing but I can express and leave that behind and I think that's the only real thing I desire when I feel that "self grief". In the past I used to think about things I'll miss out on, experiences, travelling, etc, but I came up with this personal logic that those experiences aren't really unique, billions of other people have experienced everything that I probably ever could. and this is where my focus kind of shifted into creative output. I'd rather leave a nice artistic mark that can't possibly be perceived as negative, and then maybe I'll be good to go.