As for staying rational, I try to remind myself "feelings are not facts."
There are plenty enough scary facts to worry about, I don't need to add worries/thoughts/expectations to the mix. Feelings are "just" mental events, potentially true, real, useful, but not facts in themselves.
That matters.
If those feelings lead you to act constructively, fantastic.
But name them and understand what they are. Transient mental states, that can and do change.