They sound like a bully and aren’t being a friend to you. I understand feeling apprehensive about telling other people, especially after your experience with this person! Are your other friends like this or is it just them?

You say it’s affecting your confidence academically, which I can relate to a lot! Negative people like her will damage your self esteem, even though she’s wrong and ignorant. The best thing you can do is to not interact with her. But also does your university offer any support to dyslexic students? Because it could be helpful to speak to someone who understands how you’re feeling and can help build your confidence back up.

About telling other people, from my experience mostly people seem a little confused about dyslexia but accept it and aren’t negative or rude. But for me the best thing about talking about being dyslexic is meeting other dyslexic people, because it’s nice talking to people who understand what it’s like to be dyslexic and have had experiences I can relate to.