I dreamed I had autism and everyone was yelling at me because I was doing things that normal people wouldn't do like shouting things because I didn't realize what was happening outside of my head. And I remember a swimming pool and me swimming underwater in that same dream. What does that mean?
You are having some social and peer pressure in you.
Projecting being swimming under water may reflect things you want to avoid.
This is pointing to the social pressure you currently have.
That is why you projected yourself being shouted at by people.
In other words, you feel disrespected, distanced by your peer group
and that is why you had this dream vent out.
It meant that you had a dream. Dreams normally have little to no relevance. Don't over-think it.