I feel like I wrote this... weird.

Word for word of exactly what I am experiencing. I am also terrified of becoming "out of control" with my therapist. Or hurting myself in front of her. I did that with my old therapist, but he was not trained well at all. If it became too stressful I would run out of his office, just so I didn't turn into a monster. I feel like I am possessed in those times. Like I need a priest more then I need a therapist.

I don't have much advice other then to bring it up with your therapist, maybe she can help. Maybe she can assure you she is trained and it's normal? I don't know if we're both experiencing the same exact thing it must be pretty popular in DID.