So shouldn't flashbacks reflect the specific trauma?

Alright so I developed PTSD from a school lockdown situation where a student was killed. So understandably I can be inside and maybe a tree branch or something knocks on a window so my mind might go to watching the windows during that lockdown since no one in that room really knew where the person with the gun was. Or being in a school type environment can freak me out and make me very anxious because in my mind i might be triggered to relive all that.

That makes sense...but now its like somehow my mind has associated things vaugly associated with that trauma with the trauma itself. So I might sort of lose touch or reality for a minute and think something I read about, heard of or watched will happen that I did not directly experience...pretty much just like the typical flashback but it will be nothing to do with my specific trauma.

Like the other day I was sitting outside in this spot sort of near my house with lots of tall grass and when I got up to go home for a minute i was being all careful looking around in the grass worried about who might be hiding getting ready to pop out and shoot or attack me and it took me a minute to remember where i even was...and I have never been in any situation where anything like that happened but I'm sure I've seen, read or heard of such situations....or maybe it was just hyper-vigilance and my mind was trying to rationalize what there possibly was to be hyper-vigilant about. So I don't know I think perhaps its some sort of PTSD issue but I don't understand it, does anyone else experience anything like that...like feeling like you're 're-living' something you never experienced. Kind of hard to explain so hopefully I am making some sense.

it sounds more like hyper-vigilance to me, which makes sense as a ptsd symptom, and for your particular situation in that respect. Being in the lockdown without knowing where the threat was coming from meant it could come from any direction. It sounds like the incident in the grass reflected that feeling: not knowing where the danger could come from.
I know when my hyper-vigilance kicks in (lately it's only under triggered conditions and under a lot of stress), I startle at every noise and scan for any signs of potential anger/violence. I interpret signs of anger where there are none simply because it helped me survive through my childhood. It can be very intense, and sometimes I have it mixed in with milder flashbacks, which just makes everything really confusing. I also know sometimes my flashbacks get jumbled. By that I mean I re-experience more than one situation at a time. The events merge and get tangled up in each other so the flashback ends up sounding more like a hallucination to someone else, but they are a bunch of parts of several situations that all actually happened, just not all at the same time. So in that sense, they are not flashbacks in the traditional sense.

Yeah that makes a lot of sense, probably is just the sense of not being able to see much around me and got triggered somehow. But it freaked me out because i got all disoriented and somehow before I ended up reacting by hiding in the bushes or running away or something I somehow got ahold of reality and just walked home still couldn't help watching my back on the way home though. But I could see how with hypervigilence your mind can wander into stuff you haven't necessarily experienced but things that could be potential threats.