As for me, this question about "How are you?" is as a dead end and I don't know why. I can't always answer "Fine. Thanks" and other variations with the word 'fine'. I try to use some expressions as 'so far so good, fit as a fiddle', full of beans, still alive, and there are many others.

After this article, I think I have to get used 'thanks, fine' and not worry. Or I can always say "I'm feeling a little under the weather today" because there is no the weather which fits for me, unfortunately.