Hi Sadie,
I am sorry you are having such a difficult time.

It sounds very erratic and disconcerting.
I'd encourage you to focus on how to stay safe during these episodes, as surviving this, whatever the diagnosis, is the foremost goal. Do you have a support system? Parents, siblings, friends? You have mentioned your therapist; I hope you are getting ultimate support there. Have you and your therapist set up a safety plan?
If your therapist is lost in determining a diagnosis, you could contact a neuropsychologist in order to do testing which might help with a diagnosis(es).
You could also seek another opinion. (We cannot diagnose here on PC.)
Please stay safe.

WC