The black clad lady dream

I had this dream during school finals; I was really stressed, to say the least. And my dreams (which are not dependent on the finals) were at stake for other reasons.

So that is how the dream started:

I was in an apocalypse-like world, and the people in that world were suffering. I don't remember the visual of them, but I know the suffering there was really bad. I think I saw sick and wounded people, mothers holding their babies while they cry, you know that scene.

Suddenly, a siren was heard; it was an ambulance! I rushed outside to see it, and I saw people running away, screaming, "They are not here to help us!!!" I suddenly saw a black-clad and black-haired lady with a ballistic vest and a black cloak, coat, or even a mantle with white fur on the collar and black dots on it (like those of royals).

Everybody was afraid, running to the corner of the rooms like cats. Both the people and I knew the thing that awaits us is worse than death. Suddenly, I saw a gun on a table near me, and I picked it up and aimed it at my forehead; there was a girl at the corner of the room that did the same. That feeling before pulling the trigger was odd...

I pulled the trigger... *BANG* Everything is dizzy and blurry; my ears ring, and I could barely focus. I shot again, *BANG*. Still the same, not dead yet. After one or two more times, I look up and see the black-clad lady, pulling out her own gun and saying:

"One must let others do so..."

She pulled the trigger, and I was dead.
That feeling... A mix of calm and stress... Everything was over, so I was calm; the only thing I was stressed about was what was going to happen next...

I wake up (not in my bed), I know what happens next, I am in never-ending limbo until I "find my answer" or something of the sort. I wasn't far off...
The girl from the corner of the room was with me in a classroom I don't recognize. I tried to explain to her why I killed myself, and she stopped me, saying:

"It is fine, I understand"

I don't really remember what happened next, only that I walked the school hallway towards the light.

And I was up, after this odd dream
I am still figuring out what it means...