Help! Overstimulated

So I just recently got what I thought was a dream job. I've been teaching for 5 years, starting in Metro Atlanta and then the last two in my hometown of Jacksonville, Fl. My actual career is environmental education, which I have about 15 or so years of under my belt. I've wrangled groups of 50-60 kids, elementary to high school, safely in parks, near animals, on boats, and beaches near water. So I thought I could handle a 45-50 kid classroom. I was SO wrong. The kids at this school have zero accountability in the hallways and in class, and they literally just shout and scream out of nowhere. I have anxiety, ADHD, and auditory processing issues. I have been able to wrangle even the worst classes by day two, but yesterday my classes were acting like they were all on cocaine. The noise was unbearable and I got overstimulated and just shut down for the rest of the day. It's the constant chatter that gets to me, because I'm trying to talk or have conversations with other students and these kids just won't SHUT. UP. I told them right off the bat I can't do stuff with too much auditory input, which usually works with the other kids I've had. But this school allows this behavior in other classes and in the hall (the lunchroom is psychotic). I just don't know what to do. I also know I can't mentally take that kind of class. I cannot process it without breaking down. I'm considering just quitting teaching altogether at this point, because I had three years of rough title 1 kids that weren't near this out of control. This is just a neighborhood school near the beach.