While reading, I ran across a term from 12th-century Japanese culture. The term is "Wabi-Sabi". The definition is as follows:
Sabi - a mood - often expressed through literature - of attentive melancholy.
Wabi - A cozier, more object-centered aesthetic of less as more.
Wabi-Sabi - As a single idea, wabi-sabi fuses two moods seamlessly: a sigh of slightly bittersweet contentment, awareness of the transience of earthly things, and a resigned pleasure in simple things that bear the marks of that transience.
This describes what I've been feeling lately. Nostalgic is what I was calling it. Class reunion coming up, memories, pondering the passage of time and the changes that have taken place, yet feeling "wabi-sabi" about the innocence of youth.