I don't think it's necessarily either, although it could be both 😀
I suspect that many people drink because of anxiety, and then the thought of not drinking makes them anxious. But the kicker is that alcohol causes anxiety in all sorts of ways, which we then have to deal with when we stop drinking.
Also, every part of our bodies gets used to a regular intake of alcohol, and cries out for it when it's withheld, which is anxiety-inducing in itself. We probably aren't sleeping well, which doesn't help. We can be a bit jumpy whilst the nervous system recovers, we start to absorb vitamins more efficiently, which again can put systems on red alert. We are also dealing with cravings, when our bodies tell us it's time for that glass of wine/poison of choice and complains when it's not forthcoming. That can mean stomach pains or a more general feeling of being 'not very well'. Meanwhile, life goes on as though nothing's happened, and we have to deal with it. If we stick with it, the body adjusts though.
I can't always deal with background noise. It's fine if it's music (most kinds are ok for me) or something like the News on in the background. That can help me to concentrate as I need to block it out. But two noises (eg music and someone talking, or some idiot using their phone on speaker) is awful - it's not really quiet I need, it's brain space. I don't know if I was like that before I started drinking. It was so long ago, and things have changed since then.
I think we need to make allowances whilst we get used to not drinking, but also be aware that detoxing doesn't preclude other ailments being responsible for feeling grim. If something persists it's still worth having it checked out.