If it's very sudden like that, I'm assuming it's bots. Happens to me occasionally at Sedo, and just did a week ago. A 'movie' name of mine that is mostly worthless and gets a handful of views a month, just started averaging around 35 views per day a week ago and still going... but no clicks.
Usually it dies as quickly as it began, anywhere from 3 days to a couple weeks, in my experience.
Could be something else, but that's what it sounds like.