What you've described is pretty much what I experience when I have a major panic attack.

Such panic attacks, for me, are not usually triggered by a single event, but usually by a continuously building anxiety that suddenly hits a breaking point. I'm more prone to panic attacks when I get tired, as my defenses are just lower.

I do not have a panic disorder. I do have anxiety disorders. The two tend to go hand in hand, and the treatment is often the same, regardless.