It took a long time and some trial and error, but I have finally found medication that helps (Ritalin - long acting).
I don't feel like a different person, and I don't feel like I don't have ADHD. I just feel a little more in control.
Examples
Instead of working on a side project for 12 hours straight and forgetting to eat or work on the important tasks, I'm working on a side project for 12 hours with food and drink breaks, while being aware that the important tasks aren't being done.
Instead of getting irrationally angry when interrupted and going straight back to what I'm working on, I get angry for a few seconds, take some breaths to calm down, then listen to the person who interupted me before going back to what I was working on.
Instead of wandering aimlessly around the house unable to focus on anything, I wander for a while, then decide to have a nap because I'm now aware of the exhaustion.
It really isn't a miracle drug, but my life is so much better now. Most of the time I don't even notice the effects, but I really notice the lack of effect when I forget to take them for a week.