There are several philosophical positions known as nihilism. I'll take a quick crack at the moral dimension. I will first give reference to the doctoral thesis of Richard Volkman, "Why be Moral? The Ethical Individualist Response to Alienation from Morality", conveniently available in closed stacks at University of Wisconsin-Madison.

The fully general solution starts with understanding morality as simply asking, "What do I have the most reason to do or want?" (credit to Sidgwick). Then, in noting regularities in my own behavior I should be forced to admit that I actually do act as though there's a fact of the matter here. Even when pretending to take nihilism seriously, I eat food instead of scrap metal or drain-o; I say, "I am a nihilist" instead of "Unrepentant the fish ba-zoop whirrr gharble!"

Now that it's apparent that even the supporters of nihilism necessarily regard nihilism as false, one can proceed to ask "What do I care about?" and work from the obvious things like food and TV up to more complicated notions such as friendship and awesomeness. Along the way one might notice that one must develop good habits of behavior (what we call 'virtues') in order to actually succeed at things like having friends and consistently acquiring food.

Nihilism, as a philosophical position, can be treated by reading better philosophy.

Got any suggestions?

I should have forseen that someone would ask that question.

Well, actually, I know almost nothing about "meaning of life" philosophers, except that there is this position called Existentialism. According to wikipedia:

The early 19th century philosopher Søren Kierkegaard, posthumously regarded as the father of existentialism, maintained that the individual is solely responsible for giving his or her own life meaning and for living that life passionately and sincerely, in spite of many existential obstacles and distractions including despair, angst, absurdity, alienation, and boredom.

I've never read Kierkegaard, but I first heard about him in my teens, learned roughly what that wikipedia quote says, and have ever since then called myself an existentialist regarding the meaning or purpose of life. It just made sense to me. And I now realize, to my embarrassment, that I never bothered to ask the question: "Why bother making up a meaning for life, if it doesn't already have any intrinsic meaning?" Or, if I did ask, I must have answered the question in the obvious way.

"Why not?"

Maybe Kierkegaard has a better answer. Though I don't see how he could.

Check out Learning Methods-- it's something like Cognitive Behavior Therapy, except that the idea is that if you pin down a habitual obstructive thought very precisely and then analyze it thoroughly, it's no longer attractive.