I can't seem to stop myself from generalising and making assumptions about these kids!
What are the kids doing?
The kids just annoyed me, but I'm scared that I might say something to them and then regret it
Kids often don't understand the repercussion of their actions. It's best you didn't say anything when you were angry, as it was not likely to be effective.
Yes but they should know they can't do that to an adult with authority.
You're right that they should be taught not to do things that annoy others.  It was good that you didn't react while you were angry, but when you get another chance, you should try to talk to the kids about what is and isn't acceptable, so that they can understand the boundaries.