What did the girl mean when she told me that she dreamed of me last night?

Did that girl tell you? There are two meanings. The first one was made casually by him. He dreamed of you, but nothing special. Another meaning is that he seems to like you, because only when he likes you and dreams about you every day will he dream about you. Why else would he dream about you? Do you think he really likes you? Or he didn't mean to say these words, you can think about it, don't casually. You should think it over.