What does this mean and what do I do?

Ok so I am in a long distance relationship me and my girlfriend of a year and 6 months met online and we are both 15 (6 months apart she is in 9th i am in 10th) PLEASE DO NOT PUT RUDE COMMENTS ABOUT HOW SHE MIGHT BE A PEDOPHILE BECAUSE SHE IS NOT. I love my girlfriend dearly and I know she loves me and she has depression and all and when she gets angry she'll pretend to send texts to cha cha (that answer text thing) or like a friend then immediately txts back (wrong person) and I know she does it on purpose because she only does it when she is mad. Me and my girlfriend are completley opposite. She is into like going out and stuff like that and she wants to get drunk and do drugs and everything. I do like going out but I guess I'm more reserved. Anyway so she'll pretend to send wrong txts and theyll say: "How do you perform self harm without a signifacant other knowing" yes she cuts herself and it really bothers me. But see we wont talk for a few hours and then we call eachother later she comes crying and saying she is sorry and that she loves me. So like a few weeks ago (when she was mad) she sent me an email of her thoughts saying that she cant bear being opposites with me and how she says its not fair because I live forever away and she wants to be kissed and held and wants to drink and do drugs and that she thinks i'm controlling because I don't want her cutting herself, commiting suicide, doing drugs or drinking (She is 15 i remind you) and she said she doesnt know how long we'll last but then she said she loves me. So anyway I called her up later that night and she was crying and I told her that I want to do what her heart tells her to do and everything meaning if she wants to go then i will be right there if she wants to come back. She said she wants to stay with me and that she loves me and she was sorry for being mean and sending the message. So anyway she lost her ipod on the bus on friday (she loves music dearly and is always pissed when she cant listen to it) and so she was angry then she spent the night over her friends house and everything and today at like 12 she txts me and is just so bitchy (her friends hate me btw because we broke up for 30 days like 9 months ago and i sent this mean txt cuz i was just furious and her friends read it) and she was saying im self centered and i kept asking her questions because she has depression and family probs and she got really pissed and said to leave her the **** alone. So then 20 minutes later she does that whole fake wrong person text thing saying "what do you do if your unhappy in a relationship" I know she meant to send that to cha cha. So Ive been trying to call her and she wont pick up and I know she is crying I just don't know what to do. Please help me.