Absolutely it can. That underlying stress can cause you to feel like you've been run over by a truck, even to the point where it feels mildly like the flu coming on. It's a real bummer, but here's the key: what are you doing to address that anxiety? Feeding it by running to Google to self-diagnose? Are you simply creating worst-case scenarios in your head? That kind of thing, day in and day out, really can run a person down. What we all need to be doing is figuring out how to beat anxiety. I've had reasonable results through diet change, and finding distractions during my worst times (Netflix, video games, basically anything that keeps the mind off of self-destructive thoughts).