Hello OP. I will share 3 that I can remember as vividly as if I was there in that timeline.

The first was about 7-8 years ago. I was in high school at the time.
The dream starts off with me biking in an old townhouse complex where I use to live.
Without warning, almost instantaneously a jet shrieks over head.
The moment that jet passes, an air-raid siren begins to wail. I peddle as hard as I can to the entrance of the complex.
I come out to the street and look to my right. Down the road about 400m, a tank turns and fires on me.
I'm knocked off my bike and begin to run down the street as i'm getting shot at by infantry and that same tank.
My highschool was just down the street from where I lived, so my first instinct was to get to it for some reason.
There is a pathway to the school just off the street that I sprinted towards.
My friends of the time are waiting. Fully armed, and escort me to the school. I'm given a Lee-enfield .303.
We enter the school and my friend begins to chain-link the doors. We are expecting an invasion i'm told.
An unknown foreign invasion force is invading. Everywhere. Full force, no prisoners.

This is where things got really intense for a dream.
I run up to my Grade 10 math class to take up a sniper position which overlooks the forest with the pathway.
Adjacent to the pathway is a soccer field and behind that another forest. So the only way through to the entrance of the school from my point of view is the pathway. Which eventually infantry began to come down on.
I shot 6 people before the window I was shooting out of was taking too much fire and I had to crawl out of the room.

Imagine you walk out of a classroom to the sound of 30+ guns firing and a very thick layer of smoke.
Unimaginably loud, intense, my heart was pounding so hard it went along with the thuds of all the gunfire.
There is a staircase just to the right of the class. I carefully walk down into the smoke and sounds.
Without warning, i'm shot. Very anti-climatic. I can feel the life pour out of me. I'm bleeding profusely.
I wipe my hand in it. It feels real. I'm actually dying.
The moment I die, I wake up and realize I must've just witnessed a real event somewhere or sometime.

Dream 2. I'm filming random stuff with my camera in my house.
The earth begins to shake and a noise steadily gets louder.
I run outside, all of a sudden, a thousand asteroids slam into the Earth. The ground around me is torn up.
I feel as though I am encased the moment it hits. I am shielded and observe the world break in two.
I fall into a black abyss and float in zero gravity moments before I am swallowed by darkess.

As if the Moon had just been slammed by a huge object or destroyed and the remnants came crashing to Earth or Earth itself was passing through an asteroid belt.

Dream 3. This dream makes absolutely no sense but I will try to detail it.
I am at my new highschool about 4-5 years ago.
It gets blurred at some point. I'm in the cafeteria waiting for lunch when I am approached by a figure/entity/person.
He asks me to come with him. We walk to the elevator which is just around the corner from the cafe.
We walk in, and he pulls out a keyscan which connects to an unseen scanner.
We reach the "bottom" almost instantly to what must've been 100 stories underground.
We enter a vehicle connected to a track, like a Japanese bullet train except it's made for two people only.
We shoot down this tunnel at what feels like nothing but I assume was lightspeed.
This tunnel connects to a Labratory. Here I am, for whatever reason, treated to a orientation about what they do.
They genetically modify zombies in an underground lab. Why? I don't know. But at that time, a red alarm system begins to ring and we hear that there's been a release. Without question the craziest SHTF event happens next.
I'm given a pistol and a bag full of ammo and I have to make it to the surface alive.

Dreams feel like a real world, and even now. Remembering these, they are more vivid then somethings that have happened to me in real life, they are memories of things that never existed. Hope I didn't forget anything or a huge plot hole lol. I'm not re-reading it.