Accidentally yelling at kids not knowing they were SPED

I’ve been subbing middle school gym for a few days and there have been multiple kids who have tried to cut class and sneak into the gym to be with their friends. Today there were a few girls who walked in ten or fifteen minutes before the end of the period and I was still kind of in a bad mood from dealing with the kids sneaking in earlier. When I saw them I said in kind of a loud, annoyed tone “Are you guys in this period?” They looked at me and didn’t say anything. I assumed that I must have caught them in the act and told them they needed to leave because they weren’t in this period. A moment later the sped inclusion teacher walked in the door with some more kids who were clearly sped and it started to click. I feel like an asshole.