I have it. I'm finishing a book.
The symptoms: Total focus, irritability, the need to close my door and do whatever it takes (which is a lot) to finish a novel, interspersed with excitement, joy, and obsession for detail. Also, from my office certain sounds can be heard — laughing, crying, shouts directed at certain characters.
The cure: Keep my game face on and get the book done.
The duration: Hopefully, two more weeks.
I'll be back in touch then.