After my experience was over, I had a definite letdown. It wasn't losing; it was realizing that I could never have this amazing experience again. It was marking something off my bucket list and knowing that I'm closer to the end of my life than to the beginning.
Whoa! That got really dark really fast! I got over it after a few weeks, once I found other projects to work on. I suspect that if I were not retired, work would have distracted me much more quickly. Heck, I'm taking the Jeopardy online test this week, just for fun!