I don’t understand it either, but I want to say that there’s nothing wrong with feeling bleh sometimes.

Mentioning it every time, though, is a bit much. The underlying problem most likely isn’t something your friend or coworker is qualified to handle. If you’re aware enough to know there’s a problem, then do something about it. If you have a toothache, you don’t fix it by mentioning it to everyone within earshot. You go to a dentist.