I haven't had something that I would call a nightmare since I was little. I was very sick and started dreaming about "Gornaya Gora" (this was in Ukraine, in English it translates to "Mountainous Mountain"). Gornaya Gora was a girl who lived in the mountains and chased after dogs and people. In the nightmare my grandparents and I were living in a little shed on a mountain and when we saw her chasing dogs around outside we started boarding up every crack in our little shed, but we forgot one at the top and when I looked up I saw her big bulging eye staring down at me.
I woke up screaming and crying CONVINCED that Gornaya Gora was real - it's like that night she was just real, like she was a fact of life. I kept trying to explain to my mom, wondering why she doesn't understand who I'm talking about. She took me to sleep in her bed, but I couldn't sleep at all because every little pattern in the sheet or wallpaper turned into her face and when I closed my eyes I just saw her face floating up at me. I've had two other dreams about Gornaya Gora and it was my most vivid, recurring nightmare.
I'd definitely suggest re-looking at that book. It sounds like what you learned when you talk about changing your dream is Lucid Dreaming - lucid dreaming is when you know you're dreaming. When you know you're in a dream, you can learn to control it. Most people have a lucid dream a few times in their lifetime on accident, but people can learn how to "wake up" and become conscious in their dream and then it gets really fun