In addition to the advice about a group, like if you don't have a group try to join one and talk to them and so on: In the meantime think about your limits and needs for yourself. It's okay to feel overwhelmed and you don't have to be able to deal with the stress in a certain way. You can still contribute meaningfully, if you know your triggers and are mindful of them. Decide beforehand, what to do if a situation is too much, like getting out or getting some distance or trying calming exercises.
Edit: You might even decide not to go to a protest, if police presence is too high and that's okay too. You can still connect to people and help organize or render support.
Yes, it's good that you see the western centrism now, because in its own, this post was a bit racist and invoking orientalist cliches. Like suggesting, that all non Western people are theists. Or saying, that atheism is a western liberal thing, when people all over the world actually think for themselves, draw their own conclusions and become atheists. Like every Marxist movement everywhere, for example. China, Cuba and the Soviet Union. Every liberation movement ever had to struggle against organized religion. Yes, even religious ones like liberation theology in South America, which struggled against the Vatican and lost or in part was ordered to stand down and obeyed.
A Marxist should accepts personal believes and fight oppression based on religion because it splits the working class. But in the end, while organized religion might in some cases be a temporary ally in national liberation, it has historically always succumbed to reactionary authority in the end and turned against us.
Furthermore, you're right, that the new atheists invocations of "facts", "logic" and "science" are seldom more than thinly veiled appeals to authority. They often do not define these things, nor do most of them seem to understand the many material contradictions and open philosophical questions within them. But that doesn't in itself make theism an defensible philosophical position either.