Not for a lack of trying, I assure you. It's just that no matter how hard I try, my mind won't accept it.
The thought of life and existence being ultimately meaningless (Something else my mind fights against, despite knowing it's true) is too much of a blow to my psyche to overcome and look at light-heartedly.
I'm just so desperate to have a purpose and meaning in my life, but at the same time I can't sincerely believe in any religion or afterlife. I try to "live in the moment" and "be happy and make others happy", but it just isn't enough. I need something more.
Edit: Thank you everyone for their responses so far, I do read them all. They give me something to ponder and think about, maybe even leading to a solution.
Personally I'm on the train of thought that the question of life being meaningless is meaningless in practice, at least to me. Who cares if it's meaningless in a universal sense? I have a life, people I care about, things which are important to me. Isn't that meaning?
In a bigger picture sense, I think the industrial revolution and the corresponding Enlightenment allowed scientific analysis to creep into and chip away at the foundation of western religions, without removing the reason people resort to religion. (E.g. Marx's "religion is the sigh of the oppressed creature".) In a socialist or communist society, one's labor directly develops the individual (at the same time as it develops society), and in this sense one can find meaning in developing oneself and humanity. In pre-socialist society where labor is alienated, this avenue to meaning and self development is cut off, and so in modern society the individual finds themselves constantly experiencing a crisis of meaning. Enter nihilism.
For me, the clear direction and path for meaning in modern, atheist society is to find meaning in the class struggle.
I'm no philosopher, so that's just my layman take.