I had a dream about a beloved dog, walking around with the injuries that killed her, and everyone was so sad, but I don’t remember being sad, and I just changed the dream. I was in my brother’s room, looking up stuff on the internet, practicing guitar; as I’ve always wanted to do. Has this ever happened to anyone here? Changing a dream when it’s going south, but still not being conscious of it?
I have done this a few times. I think one is pre-lucid when this happens 
That means that you are very close to being lucid, but not quite lucid yet. This is a very good sign 
Last week I had several dreams where I tried doing things, but when it didn’t work I acted as it had worked. I wasn’t lucid, most likely this was pre-lucidity.
I think almost did again tonight, I had a dream I had to slay a Dragon with Girlfriend A, and I kept thinking to myself "This is such a lame-ass Dragon’, and when I’d go to another part of the ‘World’ it was in this sort of Final Fantasy View 
. My dreams are getting more and more detailed and vivid, not that I think I’ll be going Lucid; that’s far too hard and complicated for me to be able to commit to. The dream journal’s the first I go to every morning…
Don’t believe it’s too hard. If you really believe you can do it and if you enjoy practicing every day, it’s not hard at all. It takes some time yes, but that’s quite normal. The fact that you’re having prelucid, vivid and detailed dreams is a very good sign. It’s also good that you’re keeping a DJ, which can be quite important in the beginning. This way you can have a better understanding of the unique nature of your own dreams. Thereby, it’s an excellent method to discover your dreamsigns, which can be used to develop specific RCs you can do irl.
“If you think you can, you can. If you think you can’t, you can’t. Either way, you’re right.”
Good luck!! 