1. Help your girlfriend repay the loan and make a repayment plan. The first thing to do is to stay calm, don't blame or show anger, which will only make the situation worse. On the contrary, give support and encouragement.
2. Break up. If my girlfriend doesn't reflect and deal with it personally after the help is returned, she will only get herself deeper and deeper. After all, this matter has nothing to do with you. It is better to break up as soon as possible.