Muddy water in a forgotten School: Cleansing the Shadow

"I was in a bathroom I didn't recognize, trying to wash something off my hands. The sink was already full of brown water, almost like muddy rainwater. I turned the tap on anyway, thinking it would clear, but more dirty water came out. I kept rinsing my hands even though I couldn't remember what I was trying to clean. There were little leaves and bits of paper floating around the drain. I tried to pull the plug, but it was stuck. Then the water started rising over the edge of the sink. It ran across the floor and covered my shoes. I was worried it would ruin them, which felt like the most important thing at the time. I opened the bathroom door and found myself in my old school hallway. Dirty water was coming out from under every classroom door. People were walking through it carrying backpacks above their heads, but nobody was saying anything. I saw my friend near the stairs and tried to ask what was going on. When I got close, she was holding a fish in both hands. She told me not to let it touch the water. Then I looked down and the water was up to my waist. I could see something moving under the surface, but it was too dark to make out. I woke up before I could get to the stairs."