I know you're probably cringing right now because being rejected hurts regardless of who does it, but this therapist did you a big favor. It sounds like your email was fairly thoughtful and mild, and if it made her immediately terminate therapy, then this T is not made of very tough stuff. I have criticized my T in pretty blunt terms over some kind of odd complaints, and I have faith that nothing I say would ever make her terminate with me. You need that kind of confidence in the relationship to really get into deep, dark things, so you're better off finding a therapist who can comfortably go there with you.