Is it worth it to hold on?

She wants to see me and talk to me everyday. She makes my heart beat a mile a minute. She's so amazing in every way. We're in a relationship but we're not. She calls us lovers and nothing more. Like there's not emotional attachment... but there is. She told me herself she's attached to me. And I'm so attached to her it's not even funny. But she says she's emotionally unavailable. Is it OK to hold onto the hope that she might be one day? Even if I could get hurt? Because right now I would follow her anywhere. If I leave now the hurt won't be as bad as if she leaves later... but what if she doesn't leave? What if I could have the chance to keep her and she changes her mind?