Please tell me this is a normal thing and will stop?

O was the worst sleeper ever mostly due to health reasons and trauma. She started sleeping through the night most nights around 18 months. She's been easy to put down and nothing major has changed. We recently took the pacifiers away but even that transition was pretty easy. She's refused to nap for my wife the last two days. I got her down yesterday but it involved some serious screaming (even with me in the room). Last night she took an hour and a half to fall asleep and was up like 4 times overnight. She refused nap again today and slept in the car. I just got her to sleep after nearly an hour of crying/screaming/yelling at me to sing certain songs and then freaking out and screaming "NOT THIS SONG." I gave her Tylenol thinking maybe it's her 2 year molars, so we will see. She's been happy all day otherwise but doing a lot of chewing on her hands.