Hi confusedbymyself
First a little vocab lesson..not trying to be rude or berating i anyway. I simply have a quirky vocab pet peeve.. Dissociation-1The action of disconnecting or separating or the state of being disconnected:
we in the West honour a long-standing dissociation between church and state
More example sentences Synonyms
1.1 Chemistry The splitting of a molecule into smaller molecules, atoms, or ions, especially by a reversible process.
Example sentences
1.2 Psychiatry Separation of normally related mental processes, resulting in one group functioning independently from the rest, leading in extreme cases to disorders such as multiple personality:
[COUNT NOUN]: the dissociations that one can observe in neuropsychological patients -cite oxford dictionary

Dissassociate- trans verb ' to seperate from association. -cite meriam webster.

Online dictionaries dont do well to accurately explain the difference and also the info online is often user posted and inaccurate. If you were to look it up online, majority views these words as interchangable, but the correct psychiatric term is Dissociate/Dissociation. Disassociate/disissacociati to my knowledge describes a concious seperation/ purposeful and thought out withdrawl from being connected to an affliation. Does that make sense? I hope so.
Sorry about starting off this post with that..... I am a bit compulsive about some things
As to the symptoms you are describing.. the fog, dream, oddness of surroundings is symptomatic of derealization. Like all dissociation, this many be indicitive of a DD, an attribute of another condition, psychological, neurological, or physical in nature...or if only happen on occasion or in small bouts and doesnt disturb your daily functioning or place you in harm...it is probably normal.. Most ppl exp. DR/DP symptoms at least once in their lives, most occasionally. Sometimes it has no real known cause, but can usually be traced to causes such as, mild dehydration, overtiredness, stress, and lack of vitamins/nutrients.. I call this "wakinglife brain fog"...not to be confused w/ neuro brainfog*
As far as the chatter in your head goes, I get this from time to time. As far as what causes it... heres how i have experienced "voices" and internal chatter, and what i believe causes different types i hear. Known voices of other parts "alters" (i dont like that word because it insinuates that there is a true or primary core and rest are secondary), in DID/ unspecified Dissociative Disorder, the fragmentation of personality happens young before the idea of self identity is formed so IMO the true self identity is the whole combination of all parts, intergrated and or coconcious/ incooperation. Sometimes this can begin to happen naturally as more parts become aware of realities of both inner and outer world, but usually it requires a lot of exploration and theraputic work. Can you differenciate between the voices, are they familar as in feeling being part of you? What do they talk about? Do they speak to each other or directly to you? If to each other are they commenting on your actions or speaking about you and what is going on outside? If they speak directly to you, are they demanding you do or say something that you do not want to do?...just some ponderings, for you to discuss w/ your therapist and here as well if you want. Voices that are demanding, negative or running commentary are usually more indictive of depressive/ psychotic type stuff. Voices that talk about random stuff to each other that is more like overhearing someone elses conversation that doesnt relate to or harm you in anyway except being noisey and distracting from keeping train of thought is more like some of what some folks with aDD might describe..but there are other reasons as well and i dont think it is actually included in any DD criteria, but seems to happen the more aware those of us w/ a DD become of our inner worlds. There are may other reasons for chattering voices as well.

I am most intrigued by the flashing images you describe. Idk if maybe your descriptive language just differs from mine or if this is something that i have never heard described quite how you put it... Ptsd, DD, Schitzophrenic spectrum disorders, and other pysch, phys, and neuro issues can involve visual flashes, in ptsd they are usualky flashback related, in DDs they maybe repressed memories, but some sense of familiarity deja vu maybe wpuld most likely be felt, or if true DID, other parts thoughts and memories...you wouldnt generally be aware if them idt. You may experences interuptions "breaks" in your own train of thought but it would be more like a mini brain blackout than a channel change. I have heard folks w/ schitzophrenic spect. Dis. describe flashing "movie" "tv" like images but they usually say they are projected outside on the wall or ceilings, windows etc... and usually they speak of know who is showing them these images or that the images have some sort of running theme...the only thing i can connect for myself of what you speak of is "sleep paralysis" or vivid dreaming. Dreams are often random images that dont always make clear sense and my jump from one situation to another, when you are asleep and become aware of this usually u are in someway a part of the dreams. When this happens to me it is sleep parylasis. Aware but can control, wake up, move, stuck. Clear thoughts trying to get the brain to signal to the body to wake up, open eyes, move, but as hard as i try can not get body to work. I know that there are many reasons for this but i havent studied much somatic or sleep disorders in depth although i do know i suffer from them but still need to complete neuro imaging and a sleep study to rule out other causation. I have not really ever experienced these types of images while awake except a couple of times in prolonged insomina sleep depravation.. so idk, but im certainly interested in hearing further descriptions from you. These are just some of my thoughts exps and personal research..I am not a Dr. So cant really say. I would talk to ur T and Pdoc about them and push for neuro psych testing refferal tho bc I think that ruling out brain trauma, and neuro/physical causation asap is important and can hopefully narrow down and or disclude serious stuff like cancers, tumors, dementia/ degenedegene scary stuff. Keep writing and hope u get to the botyom of the matter soon.