Hi Peaches, I am not an expert but the experience you describe sounds like it possibly could be a form of flashback to me. I wonder what it is about dressing/showering/the bathroom that triggers it?
I can relate to the coconscious battling that goes on around a conflict of some sort like writing to the T! I experience those conflicts too. Sometimes what I have done in the past(if it is about expressing a want or need to the therapist) I adult say "A little part wants to say _______ but an older part doesn't want them to do that because______ an another part is ashamed and embarrassed because _____. I like doing it that way because it honors each parts very honest and real perspective. Would something like that help in your emails?
I don't think it matters much whether the formal diagnosis is DDNOS or DID. They both have the same causes they both have the same kind of treatment and they are both valid real painful awful results of trauma. One just has more amnesia than the other. At the end of the day they both just really suck.