You have accepted your own death and the death of all others, but you have yet to accept that the things which you were quite content to keep around will also die; immaterial things like concepts, ideals, commitments and even laws of nature and of the universe.
Nevertheless, we must remain living and in the realm of concepts and ideals. One always takes a position, to which one must commit with little variation if one hopes for any incremental improvement. Even suicide is a commitment. The ideology of no ideology is a commitment, as is nihilism.
Commitment ultimately grounds one. It doesn't just give one a leg to stand on, but gives one a relationship with the future. It is up to each person, however, to figure out what kind of relationship they want to have with the future.
In five years, would you like to be happy?
In ten years, would you like to have finished a big art project?
Would you like to see your children well balanced and inspired?
Whatever your idea of the future might be, you have a relationship with it in the present which affects your life today.
You'll need to make the needed adjustments to see these consequences come about. Sometimes, we get frozen in certain commitments to reality that don't have anything to do with what we want most from life. This might be out of habit. It could just be a result of misinformation or ignorance.
What you'll need to adopt is an experimental approach to life. This should replace all notions of 'failure' and 'success.' You never fail, per se. You just learn a new effect. You have to readjust your cause, constantly experimenting on how to bring certain effects about. 'Learning from your mistakes' is the crude way of thinking about this, but I prefer to think of it as collecting techniques on the way to something else.
The very idea that you have a goal you don't know how to arrive at means that there is something that you value in itself. Therefore, you value the process of getting there no matter what it is. No other value should block that final value, that end result, because that end result should not be subordinate to anything which would be harmful to it by definition. Anything which doesn't harm your direct result can be used in service to it.
Say you want to be a successful musician. Let your every action breathe with this goal. Watch television like a successful musician. Think like a successful musician. Listen to music like a successful musician. Work your day job like a successful musician. Let everything be a meditation on fulfillment.
Even that which appears poisonous can be turned into milk and honey.
It takes a healthy dose of nihilism to turn the world on its head; that is, the world you have accepted as being full of its own values to which you must subordinate your own values. Rather, understand that every constituent value has value only in relation to a configuration in the service of something. To learn in every instant possible what the service of this or that configuration might be is the beginning of wisdom. Then, you will expand your horizons and your own values will act with rather than against the mechanics of the universe.
To love life, to be optimistic in the most realistic and revitalizating way possible, you must devalue those things which are harmful but are accepted by the world as a universal given. Find out what the good and bad are, use and get rid of them, rinse and repeat. You'll discover that life is pure action, pure potential and pure being, ever unfolding toward value and closing value within itself. You will live the light which destroys the darkness which has no destiny but to accept its coming.
It could just as well be said that the ultimate nihilistic act is obstinate optimism; but not of the mystic sort which clings to the platitude that 'everything will work out in the end,' but in the position, ever renewed in each moment, that this here before us, this perception, most of it hidden beyond vision, is home... There is no escape, there is no recourse, no rules for you to cheat at, since you are always within this great game. One might as well play.