I haven't tried a notebook or anything, exactly. I'm an author and have found that (very rarely) I'll re-read and edit my work to find paragraphs I don't remember writing. If I have some vague recollection, the writing still isn't me, you know? Like, those aren't my words nor emotions. My fiance has witnessed certain things I don't remember. As a kid, I don't believe people when they tell me I would become my 'imaginary friend' James. I don't really remember it but I also have memory gaps.
Honestly, I've had dissociative amnesia several times, though it isn't a daily or even weekly occurrence. Mostly happens when I'm really stressed all of the sudden or after a flashback (as I have PTSD). Yes, I endured my fair share of childhood trauma, almost all of it I dissociated during. I've had to rely on what others have told me with a lot of it.
Honestly, I'm diagnosed bipolar with psychotic features, so I have external hallucinations sometimes. Only, sometimes they're not external. There is a voice that is inside, maybe two. The woman puts images in my head to punish me when I do something she doesn't like. Thing is, I forget what I saw almost immediately after seeing them. In therapy, when she was brought up, that's how she enforced her commands for me to stop talking. I have a feeling that I'm gonna get it for writing this. She also likes to change my reflection, which is why I generally avoid mirrors, because it's not me in there.

I'm more than willing to accept this all as some sort of delusion but because she's so against me exploring this, it peaked my interest. After all, nothing scares her but this seems to have her on edge.