Trail runner- I think i understand what you described.
We have parts who have experienced something like this. One part recently was much baffled like you. She wrote that she didn't know if she was "becoming"more or "unbecoming" getting weaker.. as it has turned out both I suppose... at first she felt coconciousness..then she describes feeling very lonely not quite herself mixed. She reported that "her change" (the EP to her ANP protector type) had "regressed"...**USING QUOTATIONS BECAUSE THOSE ARE THE WORDS SHE USED TO DESCRIBE...NOT TERMINOLOGY***
She felt sad and weak because she felt like "her charge" had just given up..abandoned her/ trying to live/ had broken...and left her with a bunch of awful memories which she was having a hard time coming to terms with...abandoned in the sense that....well I guess what she always viewed as her counter part, life long partner either when co- conscious or not...this I think is a long hard process for some...so they go back and forth..she always could "feel" her in someway...they believe them selves to be the adult "evolution" of a couple of the original parts...
Anyway. Moving along.. she wrote she was gone but could still "feel" her or rather a "regressed version" of her. She stated " her charge had broken, given up, gone inside and "regressed back to her original form" a young scared child. Her charge had always completely identified with legal birth identity..therefore believed herself to be host. There has been much contention to that point over the years...but I'm getting off track... So what happened?..well from what I have read and what I can infer..I believe that it is part of integration and it is also another type of fragmentation. That when a part recovers their memories of their earliest trauma. Then faced with their truth, can't be fun or easy, I shutter to even imagine how it would feel..but lucky for me I have nothing to do with our childhood..so I don't think it would effect me that much...As the nature of DID is to protect the whole from knowing feeling reliving etc.. I believe that she left every other sensation of who she had become and her memories of her time out with her protector..then all that was left was the memories of the trauma and a small scared child...so where did she go? I assume she integrated by fracturing...
Meaning, she integrated all she had become into her protector and fractured her core off..then integrated into the deepest most locked away sub/unconscious part that has been holding the original trauma since it happened. Does that make any sense?... it does lead me to ponder.. because I am not a result of the original trauma but a later one..I know that when my purpose is no longer nessecary I will integrate into the front...host..original protector..S. (not body /legal initial..protector's intial.)....but what of the others who were fractured by the original trauma??..what happens when the sub/unconscious small child part becomes whole again inward..but everything they have become after is held by the outward? ..when and how do they merge?..or do they remain separate? Or does the small child simply dissolve because they have come to terms with the past and are no longer nessecary and neither is the memory?...