A rough day

Sometimes, I feel as though the root cause of my anxiety is this:

For millennia, the universe has managed to keep things goings. Even if civilisations have risen and fallen, and creatures have gone extinct the world over, there is a constancy to the universe. The sun will rise in the morning, and set in the evening. The earth will orbit the sun, taking roughly 364.25 days to do so. Every day, people will be born, and take the place of those who have passed. These things, we all know to be true.

And yet, I can't even manage to keep the two most important people in my world happy. There is always angst and anger, hurt and ill feeling. There are days that pass in which no one feels truly happy, where we all seem to be tiptoeing around one another, terrified of the proverbial egg shells.
And I feel as though the crushing weight of the universe sits upon my shoulders.
We have kept galaxies and planets, constellations and countless stars alive for millennia, if not more. In the twenty short years that you have been in existence, you can't even manage to keep your family happy. Not even happy all the time; you can't even seem to manage an even-keeled balance. 

It's days like these when I feel this the most keenly. Days when we have tried for a 'normal' family day, and failed rather epically.
And the worst of it is, I'm not even sure it's mine to fix. I suspect it is something that we're all supposed to club together and heal, which is no mean feat considering one of us is fourteen and going through the typical selfish bloody teenager phase. Familial relationships are never the fault of one, nor can one alone heal them. Logically, I know this.
But even so, I feel as though I am failing.