Let her know that it hurt your feelings but just don't make a big deal out of it, and not sitting next to her on the bus is making a big deal out of it.
I had a panic attack on Friday and someone who I thought was my friend laughed at me. It was over text so maybe she was trying to make a joke and it came across badly. I sit next to her on the bus in the mornings but now I don't know if I want to but that might make things worse. Should I tell her that I'm upset about it or just let it go? Should I sit next to her or not and risk completely losing a friend?
She might have been trying to make you feel better.....some people don't understand about panic attacks....just sit down with her face to face, and ask her about the situation (kindly) maybe you can teach her about the panic attacks and what she can do to help you through it should you have another one. I think it's just miscommunication, n it worth losing a friend over....but I would talk with her.