Mama in toddlers classroom, advice needed

Hi! I work at my toddlers Montessori school and sometimes they have me in his classroom. What are some things I can do to protect our relationship? I've asked to not be in his room and 99% of the time I'm not but sometimes, because I'm a sub, the lead or assistant of his room is out.,

Most times he's okay, but the last time I was in his classroom... he was like a different child it really broke my heart. He wanted me to hold him most of the day, pushed another child down, wouldn't really focus on his works (he is a toddler so it's not to be expected but it was way more extreme this day, it was an unusual day) he acted like he wanted to bite and then stopped himself mid frustration. It was a long weekend, and I think buddy wanted some alone time with me.

I just want to protect our attachment & make sure I'm not giving him anxiety around the event of school.

I want school to be enjoyable for him and his peers! Please share any advice you may have for this, as my head of director was gracious enough to let me know I will be in his class tomorrow.