Elaborate school shooting nightmare thing

So I had this nightmare thing where I showed up to high school (I graduated, mind you) and this kid came to class with a gun and he was going to shoot us one at a time. I was first. Somehow, I dodged like three bullets in slow-motion and managed to hide from him under someone's table (it's a small classroom, how am I gonna hide?). In the dream, it felt like I was being sneaky and that I outsmarted him. Anyway, he killed some other students and I kept table diving, getting closer to him to stop him (I think to take the gun and shoot him). Before I did, the only thing I remember is desperately trying to find the kid outside the classroom before it started. Apparently it was a dream within a dream (those happen often lately). I have a bad time with names but not faces so I hugged a guy who I thought was named Travis but it wasn't him. It's weird, my dremself knew why I was trying to prevent him from shooting the school for real. He never showed up to class so I sat down, still waiting, I replayed the scenario in my head and I remember seeing his feet and trying to hide mine and my hands. After this, for some reason was going to tell the entire class about the school shooting dream. I only said it was a weird dream and then paid attention to the teacher, who was talking about some form of writing (I'm a writer) and perked up saying "Cool! Now I can write about this dream!" And the teacher said "Good! Now you can create a hero for it" which is creepy since I never told the dream. Then, out of nowhere, one way or another, the topic from the other students shifted and I said proudly "I'm 22!" (I'm older than that) then everyone dropped their jaws. I don't remember what led to that exactly but whatever. Somehow, a note from the dude from earlier appeared on my desk. It was a conversation between us and it was dark on his end and at the bottom was a doodle of a stick figure (him) and red pen (blood). I don't remember what the last words were but the student in front of me said them in a questioning manner like "what's that mean?" I just shook my head, basically saying "you don't need to know". Finally, before I woke up, my jaw started to lock badly. I couldn't talk but I remember think-asking "how do I fix this?" and Google search images came up. My jaw hurt a little upon waking up.

After about 20 minutes, somehow I remember ALL of this (I forgot a few things but that's normal). This is the most elaborate dream I've ever remembered I think.