These are big questions. You seem to be taking me for a rationalist, though, as though I'm sayng we should depend mainly on "logic." My thinking has been influenced by existentialism. (See, for example, "The Irrelevance of All Philosophical Proofs of God," "Why Religion Shouldn't be Rational," " Saturated in Fiction: Consensus Reality as a Web of Stories," "How Christians Misunderstand the Nature of Religion," and numerous others. I could supply links, if you like.)
I address the question of pessimism in "How Pessimists Should Avoid Despair" (link below). Another relevant article that might interest you is "The Inherent Value of a Godless Universe," in which I sketch an aesthetic reconstruction of morality on the basis of an objective view of "monstrous" nature.
In any case, pessimism and optimism are psychological issues, which are somewhat beside the metaphysical and other philosophical points I'm making here (about science, nature, morality, religion, etc). How we respond to cosmic truth is an important topic, but it's not necessarily for philosophers to say.
One other recommendation is my article "Philosophy For Those Who Are Neither Vulgar Nor Wise," which presents my personal philosophical background, so you can know where I'm coming from (third link below).
