UPDATE (11.44am GMT) - this should now be resolved. Please get in touch with us if you're still having trouble finding the game in your library. Thanks!
There's been an error on the Humble store which has led to existing owners of Dear Esther having it removed from their libraries.
This is a temporary error, just a simple communication breakdown. We're removing the original from sale, not from existing libraries and we're working to fix it right now so no-one loses their game.
Rest assured you'll get the game back... these things happen occasionally and we'll resolve it as quickly as we can.