Any theories

Reminds me of that one time I dreamt about myself being chased by my dead self. It was really scary.
Don't know why, probably some kind of perturbations in your daily life mixed up with your memories.
Like if you dream of zombies chasing you, it might actually reflect some kind of weakness, low confidence you have while being in society, like you feel like everybody wants to do smthg bad to you or even less, just one person did smthg to you and you felt unable to defend yourself in front of this. Thus, your dream would transform it as a whole bunch of zombie around you, which makes you afraid and the fact they're zombies (memories) is a way to put you in this same situation where you basically will have a hard time defending yourself. That was just an example, not like your told your all dream in detail. That's just how I'd analyse this situation.
You're the only one who knows why you dream of this. Try to remember what happened, every details of your dream has some sort of connection with what happens in your life. Try to remember what would be similar to what is real. You'll be able to understand your dream better and probably won't feel scared anymore.
Correct me if I'm wrong, I'm not a therapist nor a student in psychology nor Freud. I'm just talking from what I read and understood.
Oh and the fact you're dreaming multiple times about this is probably because your brain can't put away this memory/feeling or whatever, thus, you get this dream again and again until it gets finally thrown to oblivion by your brain.
My english is bad, sorry.

You dream about the things that are going on in your life and head. And because you think about this dream alot it is something that is always going on in your head and you dream about it again. Just my theory

Google says it's because of stress... but I think I prefer the thought of dreaming an alternate universe where everyone's in a post-apocalyptic nightmare, fighting zombies and shit.

Thanks everyone for the replies I dont think it was caused by watching too many horror movies cause I hate watching those.

Thanks, i appreciate you sharing you experience with me. If I were to get into more detail basically what happened in that particular dream was that I saw that zombies were coming and I tried to warn my family but nobody was taking me seriously and they were just laughing at me so i started crying and begging them to please believe me. Then the zombies came and i yeeted myself out the balcony window and started running before getting tackled by the zombies and dieing.

Maybe you feel like doesn't listen to what you say enough and it reflected on your dream ?
Or you might want to tell them smthg and are sure they'd never listen ? (be it in the past or right now).
Well, you're the only one who can interpret it deoending of your feelings, memories etc.
Hope you won't dream of it for too long because it seems scary.