There could be a few different things at play, and it might take a bit of detective work to figure it out! Here are my thoughts on the options:
1. Teeth. Really really horrible for us around this point and we just had to ride it out. However, giving meds in her sleep might help?
2. Please bear in mind here that my guy is low sleep needs, but at that age he was on a 10hour night and 2 hour nap. It's possible that the nap is cutting into her night sleep and you could look at cutting it down.
3. Even with option 2, she could be overtired from all her disturbed nights. You could try an early bedtime to get her caught up before you start to make any routine changes.
Hth!