getting dumped is the worst feeling, esp when you’ve invested in the relationship way too much for years and years. I’ve been there. But sadly there’s nothing you can do to change their mind. I know it’s frustrating and it’s normal that you feel angry. I was too, for months. But keep in mind if you both are meant to be together, she’ll come back. Let her go for now and take care of your own mental health. Focus on yourself and accept things as it is. Trust me, if it’s not her, something better will come your way.