Usually when I'm reading something that just reads slowly, and that leads to me not reading at all sometimes. But of course, then there are times when I just don't have time to read because I'm too busy with video games or wasting my time with other stuff... Either way it tends to not last very long. And the best cure for it I've found is just forcing yourself into reading despite not wanting to. It's not like writer's block, since writing is infinitely more difficult than reading, so it shouldn't be too hard to overcome.