How do i stop thinking about her

Our relationship wasn’t the best we would fight often and i want the happiest. She told me about three weeks ago that she just couldn’t do it anymore. She didn’t feel it and wasn’t excited to see me. I constantly tried to reach out but then she blocked me on everything. I went to her house to talk to her and it was good but didn’t yield anything. I talked to some of her family and they didn’t say much. I just wish i could not feel this way about her. I know we weren’t the happiest but i thought we could work it out. I feel so sad and empty