Is it frivolous to fret? I would say yes.
But all this is up for debate.
I say this not to diminish any real feeling of worry or anxiety that one experiences, because those are genuine feelings. I have to concede that. But, in light of a Biblical worldview, what can we say about God who is Immanuel, God with us? Is human fear not the inadequacy of faith? Should we not live in the reality that God is with us; here, now, and forevermore?
just a thought.