Imagination: Good or Bad?

I have a slight problem. Actually, I don't know if this is a problem. Ever since I was a little kid, I have always loved fantasy and later on the entirety of the fantasy genre. In 5th grade I tried writing a cute two page story. Now I am in 9th grade and can write a good 50 something pages. However, when I'm not writing, y imagination takes hold of me. Everything I do to relax (games, anime, books, fantasy) is fuel for my imagination. I've compiled so many morals and have seen such emotion in other people's works that it holds me in a heavenly state. I get so excited, often picturing my own characters in the stories or using the material to help strengthen my own work's spiritual value, accuracy, etc. I put on my favorite bands and use the emotions i the song to daydream. Oh, but I can't be so normal and inanimate with such a rush building. I have to pace, or some other mundane thing. If I had hours I would pace forever. I know people don't usually pace over feels, or at least I don't think they do. I spend(waste) so much time pacing though, that it takes away from my time for finding new things, new stories, etc. There is also the fact that I think something is wrong with me. Is this sort of imagination rush normal? Has anyone else ever done something similar? Also, I want to relax and see new stuff, but I'm afraid if I do I will get myself riled to the point that my pacing will wear me out (to late, it actually has several times) or cause some sort of condition that will affect my schoolwork. It is, to put t simply, like an addiction. Um, what should I do about this? I want to do these things, but not sure if it is the best thing for my health, especially since my heart beats extra-fast for extended periods of time that is not normal compared to other people. Am I shortening my life or something? Basically, is this imagination a good or bad thing, and if bad what do I do about it? Yeah, this was really difficult to explain.