Hi, I'm a mom of a 4 year old who probably has Aspergers and who frequently experiences sensory overload. I also happen to be an OT. I've had to do a lot of advocating for my kid, as well as the kids I work with on a professional level.
Has anyone discussed these shutdowns with the teacher at a time when one ISN'T occuring? Is there a chance that if you (or a parent or other advocate) discusses the causes of one of those episodes with her, that you could come up with some sort of signal that is known only to the two of you to let her know that is happening, and you could come up with an acceptable way to get your needs met so that you can recover (and maintain your dignity!) and then carry on with your day?
For example, if the trigger is sensory overload and you need quiet or space, can you have that written down on an index card so you can hand it to her or turn it face up on your desk, so you don't need to have a conversation about it. If you discuss this ahead of time, maybe she can work with the office or nurses office staff to provide you with a quiet place to do your work until you are re-organized?
And excellent news on how well you are doing this year, by the way!