I'm having "flashes" help??

Hi since late yesterday afternoon i've been having these "flashes" they are like these milisecond visions in my mind of scenes (like places or groups of people). They all seem to be different but somewhat related, they "feel" familiar but i can't put my finger on what is familiar about them. They come into my mind randomly and if i try to think about what they are i can't remember them. I liken it to having a dream that you know you've had but can't remember. It sort of feels like dreams but could be reality, a movie or tv show. Its definately not deja vu as when i have that i can remember the vision iykwim. I always feel when i have deja vu that something bad is going to happen which never does maybe because i usually am extra careful after those visions.
I thought after a sleep it would have gone away or i could make more sense of it but they are still happening. I also had a dream last night about organising a friends funeral?? I usually have pretty vivid dreams which generally dont come true but now i'm really worried. I'm going to contact my friend today to make sure he's extra careful anyway.
I suppose the advice i'm after is how do i zone in on these "flashes" to work out what they are so i can process them. I've never had anything like it before and i don't know where to start to make my mind focus on something that it can't really remember.
Sorry if this is confusing and i really hope its made sense. xx

And i remembered yesterday that just before i woke from my nanna nap before these "flashes" started that i heard a mans voice in my ear, it woke me up and definately wasn't a dream. He didn't say any words it was like "ahh". Then ever since and still now i'm having these flashes. I really want to explore this more so any guidance on where to look, or read into it would be great.thanks