Make the call and stop torturing yourself with your own thoughts. Even better, write her a letter and send it Certified Mail so you don't have to argue with her.
God doesn't want us to put ourselves in the position to be abused. That is what will happen. She created this with her actions, you didn't. We are called to help, but God helps those who help themselves - and she has a pattern of behavior that shows she isn't willing to help you.
Yes there will be fallout. Not avoidable. Please be kind to yourself. She will be fine.