Isn't that a tough one? I actually came back to this question several times before deciding sure, I'll take a swing at it.

I would say that line has two meanings. First, it is meant to be a cranky old woman saying something to get the guy to leave her alone—to let the doctor know that even if she is sick, her morale is fine (like she's run the words together).

On a symbolic level, I would say that Granny's saying something much more profound: that she has found her balance in the ethical world, after a life in which she's had reason to fear and doubt.