"All i remember of my childhood is loneliness and feelings of inadequacy and deep sadness, crying myself to sleep with no one ever knowing, etc. I didnt grow up thinking I was depressed, but looking back, it seems clear."
you sound like the male version of me ... i had the same background & was in a very deep Depression in my 20's. i'm 43 now (well, actually i'll be 44 in about 2 hrs).
so, advice hmmm . . . one thing about myself that took a long time to learn was i had a habit of viewing everything negatively. it used to make me wanna vomit when people tried to tell me that tho ... i couldn't understand why they didn't agree with my perceptions. what in the hell is the matter with them anyway !!!
eventually, after many years of torture, i finally just started observing my thoughts. i've always been into meditation so it wasn't too difficult to do once i was open to the possibility that i may be creating my own little hell.
i'm much improved now - though i still battle demons now & then. my Depression is gone for the most part. and the funny thing about that was i actually missed it at first. i mean there was a part of me that liked being the tortured artist . . . i got some great poetry & paintings outta those years after all & i was kinda afraid my well of creativity would run dry if i wasn't always digging into the depths of my being... but that kind of intensity gets old for the people around you... i think my energy probably felt needy & heavy to them & that's why i had trouble attracting friends & keeping lovers.
i guess it's a matter of balance . . .
you are a very sensitive individual who feels deeply, yes? me too ... i like to sink my teeth into life - but it is a good thing to understand when to delve & when to skim the surface. believe it or not you actually have a choice. are you uncomfortable 'skimming' (i used to think it was boring but have come to appreciate & explore it more).
oh yeah, and another thing i finally figured out was i had no energetic boundaries... i just soaked up whatever energy happened to be floating around me (kind of like a sponge). how do you feel in large crowds or shopping malls - i used to get totally freaked out in malls.... if you have a hard time in malls i HIGHLY recommend taking a Qigung class. i know you aren't into the cosmic cookie worldview but even modern physics says everything is energy. if that is true where do you end and the rest of the world begin? think about that a bit....
as for the rest of my advice:
1) start with the book the power of NOW.
2) study the artwork of alex grey (http://alexgrey.com/) or read his book - he has a great tale about his emergence from the darkness.
3) read the book moodcure : http://moodcure.com/
it was really helpful in understanding the relationship bet. foods & brain chemistry.
4) follow any of the cleansing protocols on this site you feel drawn to
5) please rethink that darwinian dribble in your post (did you know darwin's cousin was one of the founders of eugenics? i think darwin was an elitist).
6) meditate every day
7) practice divine nonchalance
8) repeat the words "i am loved about 3 million times or until you believe it