This is going to sound a bit strange but occasionally I tend to do an exercise which involves me focusing on myself, when I'm feeling a little empty or stressed. I take time out and turn to the following exercise:
I sit in a chair or lie down and begin focusing on my breathing. I allow my breathing to relax me. If I'm stressed, I may think 'I let go of what my body doesn't need' and imagine exhausting stress through a long and slow breath out. I breath in and again focus more so on the breath out. Repeat, repeat, repeat. I then begin focusing on any sensations in my body - changes in pressure in my head, muscle or nerve twitches or movement, any change in sensation from the tips of my toes to the top of my head. I notice whether I yawn or sigh, stretch or even feel any buzzing or tingling sensations. I allow my mind to open as I relax and observe any images that may pop in. Sometimes those images or ideas can actually offer some cryptic solution to a problem I've been dealing with. As I say, a bit strange but I find that what it all helps me to do is get to know my self better. The self, of course, is not just a mental construct, it is also physical. The mental and physical definitely tie in together so it becomes an interesting exercise in observing the 2 interact. You'd be able to find guided meditations in this practice if you are in any way interested in the concept.
We're never really taught to pay special attention to our self in such detail. Developing such attention to detail may be able to help you identify the specifics of how your body feels and gradually works up into a state of anxiety (hyperactivity). Working out how to exhaust such hyperactivity could lead you to experiment a bit with the mind/body connection whilst meditating on it (the relaxed meditation exercise).
Our body really is a fascinating thing, the way it does what it does (a lot of the time without us even realising). For example, if you were to ask someone whether they noticed how they just sighed, they'll most likely tell you they didn't even realise they did. You can be almost guaranteed they're stressed in some way. The sigh is the body's natural way of exhausting stress. It's gotta let it out some way.