I've had an experience like that, where something really significant happened to me. At the time I felt completely whole and fulfilled. Years later, It's like there is my life before that incident and my life after. For a while I felt as you did, like there was something missing, a kind of longing. But over time it's changed. That feeling, of being made alive, has never quite left me. Even though the actual time is long since over, it really enriched me as a person. It doesn't feel like a memory in the past anymore, more like an imprint on me, like a part of me.