I agree that it may be time to consult with a professional. Meanwhile here are a few resources which may be of interest:

SENG article by James T. Webb: http://www.sengifted.org/archives/a...-conference-reflections-on-sengs-history

Books and articles by James T. Webb, including A Parent's Guide to Gifted Children (which mentions existential angst), and Searching for Meaning: Idealism, Bright Minds, Disillusionment, and Hope (a recent work).

The book Living with Intensity by Daniels and Piechowski.

A recent thread on perfectionism includes this post mentioning resources for understanding mindset and perfectionism.