I agree with Christina. Cut your losses.
I've been sitting here thinking how to respond to this, since, from what you describe, bipolar has little to nothing to do with the situation. She's got something else going on, and it's something you'd do well not to waste your time with. Ghosting/disappearing acts are manipulative games. As is making you worry she'd hurt herself. Let's see, clingy, moves on quickly, mind games.... this is not good, and cannot be laid at the feet of bipolar. Also, that she managed to go a whole week without a mood swing? This would not even be worth mentioning with bipolar. We aren't constantly changing on a dime, public misconception notwithstanding.
In the midst of typing this, I have seen your response to Christina. I'll have to address that separately.
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Makes me sick to the heart, Oh I feel so tired. And the way the rain comes down hard, that's how I feel inside.
--The Cure