Meaningless and absurdist thought feel like timeless concepts. The thought dealing with the absurd is very contemporary though, coming only from the Enlightenment to exist as it does today. Our whole society has been shaped into something over time that has lost meaning since the Enlightenment. The civilisations before ours show this. To take an extreme case, a Spartan child knew exactly what he was, what life meant, who he was to become, and the values of the people.
The proliferation of our discontent today comes from a lack of collective ideals, such as a unifying social objectives. You now must decide what you want, what gives you meaning, and what you will do with your life.
What works for one person will not work for another. For example a world defined by religion is certainly not something I relate to, nor are any other traditional ideas.
As another example, a life lived for family forces you to gather all that society has on offer and forces you to utilise it. In a traditional sense, having children not only means you need to provide for them from the birth to when they leave home. In contemporary society children are living at home far later, so you provide for them longer than that. Your success will influence this person you care so much for, in all there years.
In societies other than our own, the notion of a dowry will influence the child greatly. That is, your wealth is their future, just as for a young man seeking that woman, his own success can justify his negotiations.
We have come some distance from there, but still we see that in retirement years the focus of the elderly is again for their children. They help to buy the first home, the car, and help the children to later become independent. And at the end of life it seems the concerns around wills and and how wealth is shared is of the utmost importance.
The external motivation built into our society drives you selflessly to work now for the future of those you care about. Any form of external motivation or accountability is not dissimilar in effect, just as we sleep in on weekends when we are not accountable to work.
But I am here to consider a life with no motivations outside yourself. A world with no God, no family, no meaningful employment, and of no meaning in culture or society.
Rational meaning was explored by Camus in The Myth of Sisyphus in an effort to answer this issue. He starts from the point that, without meaning we then must all consider suicide. He explores that all we know is that there is man, and the world, and from there all else is negotiable from this simple relationship between you and the world. I’ll spoil the ending that Camus has arguments that fall short. (Which is worrying considering the alternative offered is suicide in the beginning!)
We all have a need for meaning, and one the world provides would be helpful. But it no longer does, we must figure it out for ourselves. We suffer discontent because not just one thing, but all things, are fucked.
Life without meaning is important for reasons relating to suicide and depression leading to anti-social behaviour. My first response though is: be anti-social, be depressed. You are right in feeling this way. Perhaps though there is an alternative (as these feeling and actions and rather boring and not necessary).
You can find meaning if you wish. But as I have come to this point saying there is no personally satisfying meaning, you must look back and consider everything else mentioned. Groups, family, culture, religion, spirituality, or meaningful work. The challenge may be that you hate all these systems as they exist. For your own sake, changing those systems is then worth fighting for though.