How can I stop having this stupid nightmare?

Okay so before a few years ago I was visiting my uncle at his house w/my family and he popped in that zombie movie where they're at the mall trying to get away from zombies. It didn't affect me at all at the time (I was freaked out afterwards but I didn't have any dreams about it and I was back to normal the next day). Then a few years later I was at his house & really was not in the mood to watch anything scary/gross/anything like that. Like I don't feel like watching someone get their eye sockets pushed in by someone's thumbs and see it. Like at the time I was in the mood where that is like class-less & tasteless why would anyone want to watch anything so evil. There was nowhere else in the house for me to go for 2 hours & plus he had the volume like all the way up. (& I've seen that movie at my friend's house before when I was 15 but for some reason it didn't affect me at all then either). So I couldn't get the images out of my mind or the disgusting feelings, I've had like 5 nightmares since (& I haven't had nightmares where I literally feel scared in them since I was like 14) of zombies & being literally scared that they're everywhere & not knowing if I'm going to be killed by them. I've dreamt I was at a mall & there was a barricade/gate and on both sides there were people & thinking I got on the right side but then not knowing if I chose the wrong side & the people wouldn't let you back over on the other side & then the department stores closed their gates & that led to being able to get outside but they wouldn't let anyone in the gates but they didn't know if there were zombies in there anyway, I've dreamt that I had to kill zombies with shovels, I dreamt zombies were literally chasing me down the stairs to the parking lot & me getting in my car w/my uncle in the car & then not knowing if he had gotten bitten & then wondering what I'm going to do next, like literally feeling the whole world was turning to zombies. & I haven't seen that movie in 7 months and last night I had a dream that I was shopping & my old friend was a left over zombie still alive crouched in the corner & was about to get me.