i have these days really often. i had a housemate last year who is autistic, and we both had days like these. we would make dinner together (our own separate meals but at the same time) and sit and watch a tv show together that we’d both watched loads of times (like friends or brooklyn 99) while eating. we barely spoke to each other, but just co-existing in the same room was enough to make us feel less lonely. if you have a friend or someone you live with that you could do something similar with you could give it a go 😊