Anxious brain. I love that!
You can try a reality check. Are the thoughts realistic or exaggerated fears?
Also, notice that the thoughts are just thoughts; nothing real. You cannot touch them. You can pull back and observe them and then observe that you are not the anxious thoughts. Then maybe you can let go of them and breathe. And then relax.
But, seriously, this takes effort! I think it takes less effort than remaining anxious and vigilant.