No, it doesn't matter, but that's a reason to take it easy with all your problems, not to end your life. People, and you, and I, take themselves way too seriously, and then all their problems expand into these monstrous tasks and dilemmas. But it's true that nothing matters in an ultimate sense. It's a reason to lighten up, and if you're afraid of lightening up (which I think you, based on some of your posts I've read) then it's reason to lighten up about your inability to lighten up.

The problem comes in when people SAY nothing matters, but don't really embrace what they're saying. They say nothing matters, and then complain about how much life sucks. If life is meaningless, then who cares? What they're really saying is "I feel hopeless."

If you want to take refuge in the idea that life in meaningless, then really embrace it, and see where you get. Like I said above, it might introduce levity into your life. There're of course other ways to find hope if you're feeling hopeless. Positive visualization, self-compassion and gentleness, prayer, and investigation come to mind immediately.

G'luck.