This did happen to me at a time of unexpected and unprecendented stress and shock in my life some years ago, a time when my world was turned upside down by loss. I found myself doing things that seemed reasonable at the time without realizing how wrong I was, how much I was acting not only against my sense of myself, but against my own self-interest, not to mention others who mattered to me. I have since come to realize that I was acting out of deeply suppressed feelings and needs, buried for decades. I wish I'd had a chance to uncover them and work through them earlier. But we live to learn...
It strikes me that Daniel has this sensation when he is in a moment of deep shock and stress, following news that threatens his own sense of security. He is aware of the shock, but it disconnects him with what he thought was true about himself and his life, and I think this is what he means. Just as in his own analogy (it was like connect-the-dots, when he thought he was drawing a train and it was a dragon, and so on...), he thought his life had a "shape" or meaning he was relying on, but the shock challenges that. And he begins acting on his long-buried feelings.