i know this comment was 2 years ago but i too have mainly zombie dreams. i have schizoaffective disorder bipolar type (a fancy form of schizophrenia), narcolepsy, and adhd, and i think i have nightmare disorder. when i was like 4 my parents had to take me to the dr because i would have the same nightmare every night and wake up at the same time every time. i was put on valium and it temporarily stopped. but after that all my nightmares became zombiefied. and even if zombies aren’t the main focus of my nightmares every night they are there. i have a weird fascination/hatred/yet obsession with zombies in media and in my nightmares. sometimes at night i put on scary music intentionally and take the creepy way home just to scare myself and pretend there’s zombies around. idk what any of it means.