I have a daughter who is sensitive to change, so I know how comforting a predictable structure can be. My preschooler is at his best when we follow a routine -- very few tantrums or whining.

I'm attaching a link to an article with information about structure.

Good luck!

I would not say you have to move him out of Montessori - this type of a school may be helpful for him in the long run; however, a good structure both at home and at school would be helpful for him to overcome some of his sensitivities. I have a nephew who has some serious sensitivity issues, and it has taken us some time to really understand and create a supportive and comfortable environment for him, but now, his confidence is up, he is successful in school and in social situations and has grown greatly. Think of ways in which your child presents sensitivity, and the occasions on which it occurs. This may let you know of a trigger which is causing his sensitivity, and you can either help him in overcoming it, or determine a way for him to accommodate the triggers. I would also suggest, and it may also sound strange, but try outright discussing it with him, even at his age. Why is he upset, what happened that made him upset, and why it is ok that he feels that way, but he should not let it bother him quite so much. Talking to him about the 'flip side' of the situation may help as well. Make sure that as you do so, you have a matter-of-fact, but understanding tone. The more aware he is of everything that contributes to a situation, the more he may understand and the less sensitive hem ay become.

When a child is sensitive to their environment, their nervous system may be hyperalert to sudden bumps from a classmate, a tag in their clothes, a new smell.  Knowing what to anticipate next through structure helps them have less to worry about.  Posting a schedule using pictures rather than words can help provide structure.  Also giving a list using pictures of what a child needs to do next can work in a Montessori setting.