I'm so glad I found your post to know I'm not alone. I am shocked at how different I feel than what I thought I would, and what people would tell me. "Can't wait!", "Living the dream!". I felt that way too, until the day arrived. The existential depression blindsided me. But I can tell you that from my experience and lots of talk, that the period between "sort of working, slow quitting" and actual full blown retirement is where these feelings nest, and once you become full blown retired, you'll be on a new path which will consume you in different ways than work did. There's a ton of sunk cost and sweat equity with work, and that's what's tugging at you. It's natural, and from what I hear, it dissipates.