What is the meaning of dreaming about zombies?

Last night I had a dream that started inside an old house were I was hiding with a sniper rifle and a tactical uniform. now the thing is I was guarding the doors and windows because the entire neighborhood was infested with fast vicious zombies. I have never dreamed about zombies before so thats what amazed me the most. weird thing is I was scared of firing my gun because I didn't want the zombies figuring out my location. all of a sudden a helicopter starts flying by so instead of firing to catch their attention, I use a laser that was attached to my gun (weird I know). The helicopter lands, a fully armed squad rushes in the house and helps me get in the chopper. now this is where it got kind of interesting for me.. all of a sudden I was in a big beautiful city all European/New York style (never been to either Europe or NY) where you could see the harbor and everything with lots of people everywhere. I walking with some friends relaxing and all where all of a sudden everyone in the city starts to vomit and feeling really bad. Now I soon realize what's about to happen since I just got out of the house situation so i alert my friends, we start running ping through people who don't feel quite good, then we see a pope like guy with what seems to be other important people rush out of the place, my friends and I go into a nice european style alley where people seem to be curious as to what's going on. after that I try to open a huge church door and as soon as I open I hear a loud thunder light strike and you could see the how the street we had just ped illuminate and people start screaming and running like crazy, we close the door of the church we just went into, locked it and the climbed to the bell tower were amazingly i was back in full tactical outfit and a sniper rifle, then i use the scope to see what's going on and see people eating and killing each other like crazy. in that moment I start to question if my friends could get infected or not but right after that I woke up. I know it sounds crazy and pointless but i woke up breathing heavily and was kind of disturbed by it. i woke up at 4am and couldn't go back to sleep.. what do you guys think it means?? if anything.. maybe nothing but it was one of the most realistic dreams I have ever had. ps sorry about my spelling and stuff