The simple and only answer to your question is to Talk. Many people say or do things that they didn’t intend to. She might have done that unintentionally.
So, you need to talk to her and make her realize her fault.
If she doesn’t change her attitude, start comparing her with other girls. She might get the taste of her own medicine.

You should tell your girlfriend that relationships doesn\’t work on comparison. As five fingers are not same so as me, I can\’t be similar to the other people. This comparison is making my mental condition very bad. So please don\’t keep expectations… these will ruin  the bond that we share. I am trying my level best and I will always give you the best.