I sometimes get myself in one of those, one long one took over a year. But nowadays it's usually the short ones that last for a few days - it's like I'm watching the shelves over and over and nothing jumps at me. I don't think it's bad necessarily. It might mean I have to reconsider my reading choices, or I have to sit longer with the previous book and let it finish its impact. All in good time. I'm sure you will get your spark back quickly. :)