Riddle Me This

My book is suddenly selling. It want 38 days with not one sale and now there have been 5 sales in six days. I notice it's on Kindle Unlimited and I don't know how long it's been on that. Could that be why? Or did one of you lovely folks do something to promote me a bit? If ANYONE knows ANYTHING, could you let me know? Thanks! And I'll be back soon and often since today is my first day off for a couple months to come.