Megan's got 47

So today at dance class it was parent visitation day. All the parents got to go into class and video and take pictures. Megan was SO BAD! Not her usual self. She was all over the place, licking the mirrors, pushing kids around, walking up to people's cameras and sticking her tongue out and putting her fingers in her ears (we call it the nanny nanny boo boo face) and not doing any of the dance moves. I was crying inside wishing for the bad behavior to stop. I had to walk out of the room to try and get her to cooperate.
After class, the aide took the kids out to the waiting room and the teacher spoke to the parents. She said:
"is there any questions regarding the class or the recital coming up in May? No....ok, well today as you can see was not our usual class. Megan was pushing and disruptive but I promise you all she has never been like this before, she usually is very good, I think having all the parents in made her a little excitable. All your kids have bad days now and then and today was obviously Megan's"
I was so very thankful that she said something. I know she loves Megan.
I don't want the other parents to think this is how she usually is....I always get such good reports from the teacher after class and today has just made me sick to my stomach. I just keep thinking that all the parents are probably saying things about Megan and it is killing me.
What got into her today?
It seems whenever the routine gets changed a little she acts up?
I have never been so embarrassed I just kept putting my face in my hands....and I kept giving her dirty looks to stop (sometimes that helps).
Too be honest I think it is me. I am the only person she acts up with...I am at a loss and so very upset. It just made me picture how the recital is going to be.