Imagine this scenario: you go to a doctor for a routine checkup and it turns out you only have six months left to live. After the initial shock, you come to grips with that reality and try to make the best of it. You constantly think about how it would be to die, and in a strange way, you kinda look forward to finally having that question answered when the time comes. Meanwhile, you do all the things you always wanted to do, all while your incoming death looms over your head constantly.
Then the doctor calls you, on the supposed last month of your life, and tells you it was a misdiagnosis and that you're actually fine, all while apologizing profusely. Everyone around you is happy that you don't get to die (yet), and you yourself are also happy of course. But part of you isn't. Part of you actually feels kinda bummed because of how you mentally prepared yourself for the worst, because the worst seemed inevitable, and now suddenly it's gone. You had the wind taken out of your sails of your supposedly sinking ship, so to speak. You're unsure of how to feel or even react to that.
How would this feeling be best described? Are there specific words for this kind of situation and the feeling that comes afterwards?