The Dip
ESPR, a very fun camp I attended, ended about a week ago. Before it ended, the organizers warned us that people tend to feel the dip afterward. ESPR is such an amazing experience that normal life can feel worse by comparison, even when nothing in normal life has actually gone wrong.
Things are fine. They just feel less exciting for a bit.
Based on data collected from past participants, we were told that the dip usually lasts around four weeks, though people experience it to different degrees. I think this is what it looked like for me:

For about two weeks, I was constantly around interesting people, doing interesting things, staying up too late, and having conversations I probably wouldn't have anywhere else. Then it ended, and I was back to normal, boring life. For me, it was actually a less fun week than usual because I was with my grandma, making sure she was okay.
Nothing about normal life had gotten worse. It just felt worse by comparison.
I've noticed this after other things too: trips, breaks from school, times when I'm with my friends a lot, and basically any period when life becomes unusually dense or exciting. There's a short period afterward when everything feels flatter than it did before. Now that it has been brought to my attention as the dip, I can put those experiences in context.
What's strange is that the size of the dip seems related to how good the thing was. If I'm happy to leave somewhere, there's no dip. If I really don't want something to end, there usually is.
For me, it helps to look forward and think about the next thing that will be dense and exciting. That makes the emotional effects of the dip smaller. It reminds me that the exciting part of life isn't over. This particular exciting thing just is.
I like to think that the dip is simply what missing something feels like when you were lucky enough to really like it. In context, it isn't a bad thing, even if it can feel bad emotionally.
At the moment, I think I'm close to the end of my ESPR dip. Putting it in context has helped, and so has looking forward to future fun experiences.