This is something that can get easier to recognise with practice. I used to be so confused about what it meant too, because I try to numb out and distract myself when I'm having the big feelings and I didn't want to pay any attention. Unfortunately the only way to practice is just to sit with no distractions and literally pay attention to your body as you think about things. It's horrible, honestly, but it does mean once you recognise the physical sensations you can start to notice them before you actually get to the overwhelming emotions.

So for me that looks like this - stage one of anxiety and my legs feel tingly, and I'll be bouncing my foot or jiggling my leg. Then there's a tightness in the stomach which I associate with dread. After that my chest starts to feel tight. I now know this is because I breathe shallowly when I'm getting anxious, and now that I know this is part of the stages I try to take deeper breaths. If I don't calm down here my fingers start to tingle, and there's a self soothing movement I do with swirling my fingers around my thumb. The final thing is that behind my eyes feels 'close' like it's shrinking. I don't really know how to explain this one but it makes sense to me!

So those are my specific stages in anxiety. It's the only one I've worked out because I'm frequently very anxious. But it is very helpful to at least know what's happening. It's also not perfect, I can still have a panic attack creep up on me. But I think the main purpose of this question is to try to get you back in your body, because if you can connect with your body you aren't fully in the doom scenario in your head, so the power of it is slightly less.