I have great difficulty talking about what happened to me as well. My therapist is moving slowly with me so I can discuss it more. I get the exact same issue as you, where if I try to talk about it my mind will suddenly go blank or spacy and I'll continuously lose my train of thought. Sometimes I also become very sleepy and can't think straight when I try to talk about it. Other times I've dissociated. When I do manage to actually get into something that occurred sometimes I will become so upset and panicked she'll stop me and we have to do breathing and grounding exercises.
It took me 3 years of therapy to bring up what happened and nearly 4 years to actually try talking about it but I feel this great relief that I can let it out of me, even if it's only in small bursts. I also tend to get nightmares after we talk about things or flashbacks, so I actually really, really don't like talking about it and will constantly change the topic when my therapist brings it up. But I realize if I ever want to heal I have to be able to confront what happened.
