Ive had this happen to me but my physician and therapist told me it was simular to sleep depravation where my therapy session was so exhausting and so emotionally charged that my body needed sleep and my brains thinking process went to minimal funtioning. once I got some sleep I was fine. I had gone through this many times before like when I dont get much sleep during finals week. I have to literally set an alarm clock during finals week so that I get the right amount of sleep that I need and I dont go into anxiety overload over the upcoming exams that way I wont just literally pass out from anxiety, stress and lack of sleep. My therapist and I now that we know I have this problem we make sure that we schedule our sessions in such a way that I have plenty of time to "come down" from the session before leaving her office if it is an emotionally charged session and we also schedule times when we just have slow low on the emotions sessions in between the emotionally charged ones. with these precautions in place this depravation thing doesnt happen so often anymore.