Having unrequited feelings for someone is painful enough, but it's a million more times agonizing when it's your FP. Not only does she not romantically feel the same way about me, she said she couldn't consider me one of her best friends even though I consider her mine (she told me at one point she did but then told me that was a lie). 

Despite both of those rejections I've been in love with her for over a year now. I kept hoping my feelings would dissipate or that I could manage them better but it almost feels like they're just getting stronger and harder to shove down. I go from being okay with devoting myself entirely to her to breaking down crying because the pain of my unrequited feelings and wanting to be more to her hurts so much. After all this time it doesn't seem likely to change.
I don't know what to do, if I should try to learn how to manage my feelings better or end the relationship to give myself time to heal. I don't think I've ever loved anyone like I love her and it makes it so much harder to think of parting; she's also the only FP I've managed to have a relationship with longer than a few months. She's more affectionate with me than previous girlfriends and it makes me confused (she had said she is most likely aroace).
I find myself desperately wishing our relationship will become something more even now and it feels wrong to both of us. 
(Sorry, I have a tendency to ramble.)
Tldr; same question as the title.