I have a panic attack all day before therapy? I only came to my therapist to help with setting boundaries, but she really wants to dive in deep into my lengthy trauma. I'm incapable of doing anything before and after my therapy sessions because I become so frozen in panic that I sob until I'm so exhausted I pass out. 
I've had a very traumatic experience with an ex-therapist that I don't feel comfortable getting into, so I'm unsure if maybe that's why this is so difficult for me?

My question is, how do I tell my therapist I need to stop having sessions? I have nightmares about therapy the night before, and it just doesn't feel safe but I feel guilty for leaving her so soon into our appointments (I've only had 4).
Should I just stick it out? I'd love any and all help.