I can’t find the right words to describe this feeling. Is there a book that captures it?

It's more like pain and a feeling of loss. Not nostalgia exactly. More like grief and a feeling of injustice. Like I was supposed to be in a different universe altogether, living a different life and someone locked me in this one where I have a completely different life which feels like a dream. Flat, uneventful, and colorless. Emotionless. Like there's someplace, some situation I have to remember and go back to but there is none. I was supposed to be somewhere else but I don't remember where. That I need to wake up but I can't.

Or being reminded that you lost something, that you were supposed to be somewhere else and someone else but instead you're here and there's nothing you can do to get back to where you were supposed to be but there's no such place because you were technically always here. Like you remember something that hasn't happened and it pains you because you lost it but there are no concrete memories just a feeling. The feeling that you were supposed to be somewhere else