Despersonalization is a common symptom of anxiety. I used to have it happening to me almost every day. When anxiety hits me the hardest people become irrationally scary, the noise seems to float all around you but never entering your ears, the thoughts race and then, everything becomes nothing. The best I can describe it is when your soul leaves your body and walks it on a leash. It's like you aren't in yourself anymore and it's awful. I often looked at my hands and they didn't look mine, people talking to me passed me by.
Here's an illustration I did after a day it hit me hard. I was in a mall when I became paranoid and I was with my boyfriend which I used as a wall to protect myself from everything. He took me to the bathroom and washed my face and made me focus on the feeling of the water.