A clinical analysis of what you're describing, particularly because we're on a pro-choice suicide forum, might result in a label of "depersonalization", but I think this is a common enough experience.
We change so much over our lifespans in response to our experiences and environments that it's actually amazing our brain can construct a unitary Self from the chaos of it all.
In Buddhism, the Self is in fact considered to be illusive. Based on my personal experience and what I have read of Buddhism in the controversial book, "What the Buddha Taught", I am inclined to agree with this perspective.
I know that I haven't felt more like my past self as a child in years. A psychologist or therapist might say I have regressed, but how do they know I haven't rediscovered a valid part of myself I have buried to fit in? It's not a particularly cooperative or successful personality, for sure, but I feel as if I have awoken from a dream and again see clearly just how alienating and inhumane our society has always been.
Whereas in the intervening years I saw my childhood as more of a dream (more a waking nightmare) and my then perspective as more real, now the opposite is true.
