Zombie fears
For a while just after I'd moved into my new apartment I started having irrational fears about zombies being real. I knew it was ridiculous and yet late at night I'd think about what I'd do if the movies ever came true. What always had scared me about zombies is that your allies and loved ones can turn against you in a second so you would just have to fend for yourself. Sometimes in the morning when I'd leave before the sun came up I'd have a moment where I'd wonder if everything had changed over night while I was asleep and I couldn't tell because no one else was up yet.