CFA® candidates have to face the very real possibility of failure.
As the CFA exam is no ordinary exam, the high failure rates actually mean that there is significantly more disappointment than the average qualification. Also, CFA candidates tend to be overachievers - i.e., not used to failing. I had my own bittersweet experience in this once in Level II, so did others.
So how should you adequately recover from not passing your CFA exams, and ensure you bounce back stronger than before?
Feel sorry for yourself for a while.
It's normal and allowed, and you should go through this phase. You've put in a lot of effort, so it would be absurd if you weren't disappointed. Allow yourself a week or so to mope.
Pick yourself up, and realize that in the grand scheme of things this is just a blip in your path to greatdom.
Although the impact is devastating right now, eventually this will reduce to being a blip on your path in life. Thinking about the latter part will help you put this experience behind you and look forward.
A useful trick I've learnt is to think of yourself 10 years ago, and at that age, what crisis were you going through that made it seem like the world was ending. Chances are your 'crisis' 10 years ago seems very silly to you today. That's how you'll look back on today 10 years from now, so really, it's not a big deal.