A very intriguing question. It asks for a subjective answer first then and for an objective one - in my opinion. Quickly, in the moment of "NOW," I am relating to a movie "Jacob's Ladder" (http://en.wikipedia.org/wiki/Jacob%27s_Ladder_%28f...
I experienced amnesia, both retrograde & anterograde, in 1978 and have been trying to answer your very first question ever since.
To answer the second question "Why are we here?" I have to ask a question - who is or are we? In the moment of NOW, in my opinion, we is whom or what, since animals and plants and all kinds of things are alive, or even the audience reading, writing, and interacting here could be the "we."
I have learned to long of answer means a hub, so I will end it with you chasemillis have presented great food for thought.