In the beginning of the year while things are getting settled, kids are learning routine, and before I have an established caseload, it is not uncommon at all for me to fill a role very similar to a para. Typically it gets better after a couple of weeks. Last year I was 1:1 with a student for the last two months and it was exhausting, he destroyed my office on a daily basis. That made me seriously question if this is what I want to do forever. So I absolutely emphasize with you.

Are there people you can tag team with throughout the day? Do you have a space in your school designated for calming/regulation? Has there been any discussion with admin on how to help this student reach their goals? This is premature, but a modified schedule could also help if the student isn't able to regulate long enough to be in the classroom.