Vampirical writing?

I had an interesting discussion the other day with a friend who is pregnant, and the topic turned to how some babies seem to require so much energy from their mothers while still in the womb. She mentioned the last Twilight book, and how it was like a vampire baby, taking all the life of the mother.

Now, she's very excited to have a child, and it was just an interesting and funny conversation, but I can't help thinking of how that relates to writing, and mine in particular.

For the past two weeks I've been writing feverishly. My newest book has taken on its own life and consumed me. I can't seem to do anything else at night or on the weekends but write. Any other activity feels like I'm wasting time when I could be writing.

This very well could be my ability to hyperfocus on just about anything. I really do have a one-track mind when it comes to something I'm passionate about. But I wonder if other writers ever experience this. Does writing your book, or thinking of plot, or brainstorming characters ever become so all-consuming that it's almost like the booking is sucking the life out of you so that it can live?

That's what I'm experiencing now, and though draining, it is exhilarating. I love every minute that I can sit, unfettered and unbothered, and write until the words dry up for the night. But then I go to bed and can't sleep because I'm thinking about what happens next, what turmoils my characters are facing. I'm living vicariously through them for a time, but it really does feel like I'm living a life much more exciting than my own.

I'm almost sad for when that time will end, but I've a few weeks yet before the story is completed and I start into the revision process. But as a writer, I know I'll jump right back into another story when the time is right, ready to give my life over to another mewling book desperate for its creators attention.