Yes.

I hate how, in our society, something being in our mind is considered a pejorative.

Our entire worldly experience is filtered through our mind. So in that way everything that we experience is only in our mind.

That doesn't mean what's happening up there isn't having real physiological consequences on our body and our daily functioning.

There are, of course, things that we can do to mitigate and work through anxiety just like any other pain or illness but the fact the anxiety exists in the biochemistry of our brain does not make it any less real.