So, at some point during consensual foreplay, your ex dissociated. When the episode ended she didn't realise what had happened or what was going on, is that it?
If it was her first sexual experience post-abuse, she may not have realised it would cause her to dissociate, and depending on where she's at with recovery, she may or may not be aware of what a dissociative episode is. And I can understand that would be pretty frightening for her.
You are not responsible for the dissociative episode. But if she doesn't understand what's going on, she may be panicked about what's happening. She may not recall that it was consensual.
Has she made a complaint to the police? If you have reported the incident to the police, then you may need to speak to a lawyer. There may be legal aid available for you (not sure for your jurisdiction).
Regardless of what you've already covered with the police, write it all down. Take your time. Everything you can remember from when you caught up, conversations (at least general comment), plenty of detail about how the foreplay started, how it proceeded, and what happened when she came round, and then what happened afterwards.
You don't need to give those notes to anyone. Date them, sign them, and keep them safe somewhere. The more detail you can get down the better. Include details about why you knew she was consenting
This is not a time to panic. If she files a complaint, definitely speak to a lawyer first. But she may not. The situation is obviously different if either of you are underage.
Like I said, you are not responsible for her dissociating. What you were doing may have triggered it, but that does not make it your fault.
Breathe. Stay calm. You're going to be okay.