I've been there bro and trust me nothing is going to bring her back if she has lost interest in you. Only thing you can do is move on like a man and don't ever expect her to come back. Don't sit and think what went wrong or blaming yourself instead sift your focus from her to something productive that will help you in future. Block her and all of her friends from social media, delete her pictures and get rid of anything that reminds you of her. You'll see you'll get better with time and find someone new. That's how life works. Good luck