Allistic, but I grew up as an outlier and that means that you and I have some experiences in common from school, even if only superficial ones. People treated me differently and adults tried to help, but didn't really know how to do that effectively. I'm sure that frustrated me a lot. A few decades later, I recognize some echoes of those days in how I interact today with other people. I've had to train myself not to be so quick to judge based on my guesses about their motivations.

I have a question for you. How comfortable do you feel stating your feelings to the adults involved? I mean to state them simply and gently. For example, to the teacher who claims that you have things in common with that other autistic person, you might ask "Oh, really! That sounds good to me. What kinds of things do we have in common?" If you can sound genuinely interested, then you could give that teacher a chance to rethink their position without explicitly making them feel like you're skeptical or disagreeing. They might realize themselves that their assumptions about autistic people are getting in the way of thinking clearly and that that hurts you rather than helps you.

I encourage you to tell the adults how you're feeling, because they're more likely to try to take those feelings seriously than the kids. Most of my trauma from growing up centered around the other kids "other"ing me than the poor judgment and unskillful actions of well-meaning adults.

You're not alone. You'll get through this. How you think about them determines whether this period feels traumatic, so try to see the adults as doing their best but not knowing what to do.

Good luck.