Hello concerned,
Welcome to SR! You might want to check out the Friends & Family section here. Here is a link.
Friends and Family of Alcoholics - SoberRecovery : Alcoholism Drug Addiction Help and Information
Your GF's actions concern you. You cannot control her. What role does alcohol play in her family? Any future indications or patterns of behavior evident? Learn a bit about the progressive nature of alcoholism. It will help you assess this situation and your responses to it.