The bottom line is: she needs intake. Adequate intake daily. And nutritious intake. Which Formula or breastmilk is. It is more nutritionally dense, than solids.
Like Riley J. below, I went by my kids' cues.
Fed on demand. Per nursing and "food."
Nothing is static, with appetites or food wants... so you need to be able to gauge your child and flex with it.
And when teething, with my kids, they did not want to eat either.
I was breastfeeding, so they just had more of that and more often.
Food tastes and wants, CHANGE all the time. Everyday. It never stays the same. Their taste buds are also, changing and developing. And they are experimenting. What they eat now, will not be the same thing they eat months from now or a year from now or years from now. That is, normal.
Even for adults... we don't always want to eat the same thing, for months. Or we change in food cravings. Just like kids.
Just make sure she is getting Formula or breastmilk, too. Because, it has all the nutrition in it, she needs. Even if she is not "eating" much.
You don't want her to get dehydrated. As well.
Try giving her a frozen little washcloth. Dampen it lightly then stick it in the freezer. My kids, loved to knaw on that when teething.