Sometimes in school years people go through changes with how they react toward people because they're getting older and learning new ways of dealing with the world. But as they change, they are usually becoming who they are going to end up being for the rest of their life. A friend who is embarrassed to be seen with you is not a friend, that is a user. Users care about getting and never giving in relationships.

If you can talk to her about how you're feeling, say why it bothers you and ask that she please change, you really need to base your decision on her answer. If she realizes the pain she caused you, she will apologize and you two can go back to before. But if she still says she's embarrassed by you, it means that she doesn't really want anything to do with you anymore unless she needs something. That's not being a friend. I've had people do this with me so I can understand what you're going through. Good luck and please try to make the right decision for yourself.