[there is term called "repressed memory". it's caused by the mind being on overload with the information. like too hard to process. in children this often happens when there are things that happened that were too much to bear emotionally. so they become repressed or for better words, lost memory. it's in there, just not on the surface where one consciously remembers it cause the mind is protecting you.
that's my spin on it. i could be incorrect but i'm feeling like your T has some insight on this. why not let her guide you thru this process of discovery if she feels it will help you. if nothing's in "there" then you can move on to the next "topic".