Heh... Oh yes, I know this feeling well...
To be perfectly honest, a lot of the time I just trudged through it. There were times that I was under such a constant onslaught that I had no energy left for self-care, and sometimes my knowledge that I'll be fine gets in the way of me making the effort for myself. But when I don't let it get in the way, a couple things of particular use to me...
Gina's suggestion is a good one. Exercise. A lot of it. What's happening in your brain is that it is now expecting to be attacked all the time, so it's pumping you full of completely unnecessary cortisol so you're ready to move. But you don't need to move, so it just sits there... giving you the fidgets and making your mind race. So, you have to burn it out of your system. Run, find something to punch, lift weights, whatever suits you. Just burn it off.
Along a similar line, I like finding something to be pumped up about. A mission. It's better than just looking for a fight.
When I'm on a mission, there's no room for anxiety. But this might depend on whether you have that "BURN EVERYTHING!" sort of setting in your brain. Not everyone does. I was never anxious when I worked on a paper -- always on a mission.
Talk to people. A lot. Not necessarily about what's troubling you, but just talk to them. It helps keep you in your body and aware of the world, rather than caught up in your thoughts.
Also towards the end of staying in the world... take your shoes off and go stick your feet in a lake or a river or something. I'm serious. Sounds silly, but seriously.