Do I trust her?

So when I moved to my new school five years ago, there was one person who was there for me, everyone else hated me. She was my only friend and best friend for three years, we were so close with each other. Then one day she just hated me, she kept telling me I did something to wrong her, but we hadn't spoken that whole summer so I had no idea what I did wrong.

After that stressful year, she began helping the people who were ruining my life, she constantly yelled at me telling me I was a terrible friend and I was worthless. But, I never believed her. She was just like everyone else. I was a good friend to her, to everyone. But then at the end of last year, I had enough with her. I yelled at her for the first time in a long time. I told her I would never trust her again and that we would never be friends ever.

Now this year, she called me, but acted like it had never happened. Like the last two years never happened. I am so mad, I am so sad. I have so many mixed emotions right now. She broke my trust and smashed my heart. And she expects me to just forgive her? What do I do?