My friend thinks she did nothing wrong?

So, I asked my friend if she could stay the night. She said she had to clean, she couldn't. She didn't even ask. Then I find out, 10 minutes after I asked, her friend asked. And she said she's going over there. Now, for 3 weeks I've been asking her to stay the night. She keeps saying 'Tomorrow'. But never can. So I get really mad, and say that she hurt my feelings, and I was extremely mad at her. And she says, 'But she leaving for three weeks' I said, 'You said that last week she was leaving, but you'd see her when she got back.' And then it turns into a huge thing, and she says I don't see it from her point, and then she gives me a bunch of excuses. And I tell her 'So.. thats what I get for begging my mom to take you to cedar point with us. And now I don't get to go because she's mad at me.' And say whatever I'm getting off. And she says whatever. And so, do you think she has done something wrong? I see where I might have overreacted, but figure she's been doing this for 3 weeks. And I'm about done. I hate to stop being her friend cause shes my only friend. But I'm sick of it, she doesn't think of anyone. What should I do? I'm really really really mad.