I would like to say thank you to all the wonderful anons here. One of you posted this song in /mu/ this last January or February.
https://www.youtube.com/watch?v=7ympaDJDTFsI remembered and am listening to it right now and it's nearly brought me to tears for the first time in over a decade. That time wasn't a particularly bright time in my life, it's about as close as I've ever come to becoming a true hikikomori.
Listening to this song makes me remember being wrapped in my warm blankets for days at a time, barely even leaving them to use the bathroom. I remember watching the snow drift past the streetlamps at night then melt through the next day. I remember my hair growing long as it slowly covered my ears, fell into my eyes, and brushed my shoulders. Disappointed voices outside my door and spider bites that appeared in the night. Only creeping out of my room to eat, drink, and piss when I was sure that everyone else was asleep, because I was so very scared of being seen. Feeling like something out of a 12-year-old's first creepypasta, like if some drowsy sleepwalker stumbled upon me they'd be scarred for life. Losing my humanity day by day but feeling so warm and so oddly content at the same time. I remember feeling so peculiarly childlike and bittersweet about the whole thing. As if I owed the whole world an apology. And now, even as that time is squarely set in my rear view mirror, I feel as if I would quite like to go back. If you have been in a similar place, I'm sure you know what I mean.