I hate everything about you, why do I love you?

Hello everyone! So as quick as my awesome mood came yesterday after recieivng myschedule in the mail, it was gone. Thanks to my good old "friend" I told you all about previously. I call her D. We are in this weird relationship thing, yet it's not a relationship at the same time. I don't know what to think. She makes me crazy.
 So she gets back from being away for two weeks. I sent her letters. A CD I made for her. Little joke gift. Texted her many times. Recieved absolutely nothing in response. She got back today and didn't bother to IM or message me. I sent her a message on FB asking if she recieved anything I sent her. I was very upbeat and happy and loving in the letter even though I am boiling mad. That is how our relationship is. I act like she can do no wrong and assure her of that, when in reality she can be so damn selfish it absolutely blows my mind. 
    I constantly feel not good enough for her. I try so hard to help her and worry about her so much. Her circumstances are not good. She needs help and doesn't get it. I put it upon myself to give it to her. I just love her so much that I can't even tell you. I never knew it was possible to hate somebody but still love them more than anything. I will say that's it, I'm done with this, but then she holds my hand and nothing else matters.
 She does not care about me HALF as much as I do her, and I know that, but couldn't she at least bother to write back to someone who took so much time and effort to care about her? Why am I not good enough?
 
I just love her. I shudder to think what I'll be like in an actual relationship. I'm going to be the stupid girl who kept going back and getting beaten up until she finally gets her head bashed in and her heart broken.
I get kicked and hurt and what do I do? Go back for more.
When I have my first real relationship one day I will tell them they're my first love but it won't be true. D will always hold that spot, maybe one day it won't be this hard but a part of me will always be holding on to her hand with all my might.