Hi and welcome.
It's okay. Don't panic. Everything is going to be alright! Labels are just things to describe something that is already happening for you.
As far as ego-states go, everyone has different parts of themselves or sides of themselves. Its just that when trauma happens to young children they can't integrate their experiences, so those states or sides or whatever label you want to call them are a little more separate or dissociated from each other than with other people. But it's okay, with therapy people can resolve the trauma and lessen the dissociation between the states of self over time.
It's not a big bad boogey monster and you're not a freak and it will be okay. Okay?
It's a really good thing to know what's going on because then you can figure out what to do about it.
And don't worry about the labelling too much. Sometimes people get a bit hung up on making sure that everyone is using exactly the wording they think it should be, but squabbling about that isn't super important right now. You T has told you, you have a dissociative disorder and you are feeling a bit freaked out by it all. THAT'S the important bit. Just breathe, and take it slowly. It's a lot to wrap your head around at first!