There's a girl in my class (there are about 5 other people in this class) and every time I say something, she turns to the girl next to her with a huge grin on her face. She does it EVERY TIME I say something. She never laughs out loud at anything I say, so I can't accuse her of anything.
I'm not being paranoid, because my friend heard her say she dislikes me. This girl keeps doing it and I've asked my teacher to tell her something, but she said she wouldn't say anything because she doesn't believe me. Is this normal? Has this happened to anyone else before?
I'm not being paranoid, because my friend heard her say she dislikes me. This girl keeps doing it and I've asked my teacher to tell her something, but she said she wouldn't say anything because she doesn't believe me. Is this normal? Has this happened to anyone else before?

If that's not the case, you may be the source of an inside joke or she is just screwing with you.
Bottom line, ignore it as there's nothing you can do. You could start making up your own reasons for her doing so, which might be fun.