Ask her for a proper reason and if still she is giving up on you so easily then she ain’t worth it. You should focus on yourself :) and trust me when the right one comes along she won’t leave you :)

Hey! Thanks for reaching out. Right now what’s very important is how are you feeling about it? Do you want to give this relationship a chance or want to end it? You can try to talk to her and explain her how you feel. Ask her what she wants and what are her expectations from a relationship. If she is willing to give this a chance then decide you both want to work this out. If her decision is final then don’t push yourself in her life. You can talk to her and have a closure. You will feel bad about it for a while but it’s better to have mutual feelings in a relationship than one sided efforts.