Growling

This was my first time actually being able to do a lucid dream on purpose. And it just so happened to be a nightmare that I have had before. It was middle of the day I was sitting in a medow with a pond with my right foot in the clear water and suddenly the sun was setting and it started to get cooler I got up and was starting to walk away from the water when suddenly a dark shadow was looming over me. I did not turn around, but the hair on my arms and back of my neck were standing on end and I started to run to the house. There was a large Weeping <PERSON> and I nearly tripped over the root caught myself before I could trip and I ran into the back door...like literally ran into the back door before I was able to open it and slam it close. As soon as I slammed it shut whatever was chasing me slammed into the door. I ran up the stairs, ran down a long hallway and I could hear heavy footfalls on the stairs. I stopped at a small door opened it, and fell down a long dark tunnel and into dark blue water, I could only see a little past my chest but other than that the water was dark. I heard whatever it was that was chasing me make a horrible growling noise and I dove under the water and swam through another tunnel where I came up for air there was a table with a chest on it, a small night stand with an old school tv with the rabbit ears on it. I do not remember what was on the tv, but as soon as I got to the chest I woke up. Just like always. Does anyone know what this means I have been having this nightmare for the past year, the house is always the same as well as the tree, but everything else changes.