Girls, I'm panicking. We started having trouble falling asleep, we nev…

Girls, I'm panicking. We started having trouble falling asleep, we never had problems before, we used to fall asleep quickly, but lately she's been playing in her crib, spinning around and today there were tantrums at lunchtime, and now in nighttime sleep she's been crying for an hour straight, I don't understand what she wants ? Has anyone experienced this? Is it some kind of temporary period? Or did I miss something? I don't know how to react and calm her down, this has never happened before.