I hate my brain sometimes : ADHD

It’s 4am, I have to be up in 6 hours for work, but my damn brain won’t shut off because I had an idea for a new dnd oneshot or some friends based on a book series I love and it keeps coming up with ways to alter existing stats to fit the setting or thinking on how I would structure the story. I just want to sleep, and I really need to because I have a busy day coming up, but my brain just won’t shut up. Even more frustrating is that I’m coming up with some good ideas now but I know that when I actually have time and resources in front of me to plan I won’t be able to come up with diddly squat.