Back from break...

                Today as a new teacher, I had one of those days.  One of those days where all I can say is "middle school is rough". The read to lead group I teach was not on their best behavior. It’s like they regressed over Spring break. I was just bragging about the strive they’ve made with their behavior and then they come to our meeting as if they forgot our purpose. The talking wouldn't stop, they did not listen to my instructions and argued amongst themselves. I felt so sad that they behaved this way. When I asked them why they respond to me yelling, they said I don't yell I  just look upset. And, that they are used to mean teachers yelling at them: followed by naming my colleagues who "yell". What am I supposed to do? I am at a loss and would like to know what some other teachers would advise me to do.