What should I do about this problem? (10 POINTS FOR BEST ANSWER)?

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I'm sorry its a bit long, please help me it would make me feel a lot better if you could take the time to read and write a good answer. Me and my girlfriend get on ok, but things seem to have turned sour. She doesn't eat much of her food and she said she doesn't care if it harms her because she doesn't care about her body. I told her that she needs to eat so that she can see her faviroute singer again (she goes to all of his concerts, and has met him on once occasion), she was a little bit angry about this saying that she doesn't like it when I use band members of bribes. I told her later on I'm sorry and she said it was ok. (she later posted on twitter, "using band members to bribe me will just make me hate you." - she didn't address it to me however.)

Before i went home from her house we went on skype and she called a random person (we sometimes play tricks on random people on skype). We talked for literally half an hour with some random person, it was so boring yet she seemed to want to stay on anyway. She eventually ended the call and kissed me goodbye.

I asked if she wanted to meet up tomorrow (saturday - today) and she said it was the day her family go to town (it is). I asked about Sunday and she gave a vague answer. When I got home she had posted on twitter, my boyfriend needs to learn sarcasm there are a lot of things I hate about (my name) but at the same time I love them. She called someone else on skype but she called ugly and was ranting saying that she knows she's ugly, but its my body and I can look how I want. I saw her post and asked her by PM if she was ok she said "yes i'm fine". I replied saying ok, but if you need to talk you know where to find me.

I don't understand what's happened, the early part of yesterday we were getting on well but now things have gone downhill. She was the one who asked me out just one week ago, and even yesterday she seemed to like me. Today she hasn't used twitter much but I know she feels down.

1. What should I do - should I contact her later, or leave it?
2. Is our relationship damaged - or does she need space?
3. Is she angry at me or just having a hard time (I have on multiple occasions wondered if she is depressed because she has low self esteem and she always politely rejects compliments from people).