I'm no doctor but doesn't that just mean that the olanzapine was treating the psychosis and the psychosis came back after you stopped taking it?
I'm not really familiar with the dopamine hypersensitivity thing you mentioned but doesn't it just mean that you needed olanzapine?
Why can't you just go back on olanzapine? Was it causing adverse effects?
Also, from my experience, psychosis doesn't go away, but it is treated by antipsychotics. (That's just been my experience with having psychosis).