I would be upset too. And you have every right to be. She ditched you after you gave so much for her and she left you alone. Not only is that mean its very dangerous. I would tell her straight up why your so mad at her and make her feel bad so that you get your point across to her. I have best friends too and if they ever did something like this to me I would want them to be aware of how bad they hurt me. I would forgive them if they did say they were sorry but there trust would have to be earned back. I hope this helps with your issue with your friend and everything works out.