Dog chase Through old School and paper Bag

"I was walking home with a paper bag in my hand when this dog came running out from between two parked cars. I couldn't tell what kind it was. It wasn’t huge, but it had this very serious look on its face and kept staring at me. I started walking faster because I thought it was going to bite me. Then it started running. I dropped the bag and didn't even stop to see what was in it. I remember being weirdly upset about that, like whatever was inside mattered more than getting away. The street changed into the hallway of my old school. The dog was still behind me, its nails clicking on the floor. I tried going into a classroom, but all the doors were locked. When I looked through the little window, people inside were watching me, but nobody moved. I finally climbed onto a desk and pulled the door shut. The dog scratched at it for a while. Then everything got quiet. I opened the door a little and saw it sitting there, not growling anymore. It looked tired. I felt bad and reached out to pet it, but it suddenly had my neighbor's face. That's when I woke up."