It seems my luck has been down lately. I started playing a gacha game and got really bad pulls. With a 3% chance of getting a 5 star, I wasn't able to get a single one after 100 pulls.
The odds of that happening aren't absurdly low, but it's still under 5%. (0.97 to the power of 100)
My luck is usually very good, so I guess it just has to balance out a bit.