First have your doctor check her out to make sure nothing is going on.
Teething, ear infections, tonsils, hand/foot/mouth, etc all can cause some pain and discomfort and she might not want to eat if anything hurts her.
If she needs something to chomp on due to teething - try giving her a frozen waffle.
If the doctor has checked her out and there's nothing he can find going on, then you limit how much milk she has per day (something like 2 cups per day is plenty), offer watered down juice or water to drink and offer her healthy foods to eat - whether she eats it or not is up to her.
If she doesn't eat, then put it away and offer it to her later.
Give her tastes of food off your plate.
Our son went through a stage where all the food he ate HAD to come from my plate.
If he liked something, I'd take a portion from my plate and put it on his.
At night - all she gets is water. Period.
Doctors and dentists will all tell you the same thing on that point.
Try soft foods/cereals (oatmeal, cream of wheat, etc), par boiled carrot sticks (so they are soft and easy to gum), baked fries, scrambled eggs, yogurt, cottage cheese, mashed foods (potatoes, sweet potatoes, squash, etc), soups are great, some crackers/cookies (don't go overboard on these).
Brush her teeth and gums with a soft toothbrush before bedtime.
You also need to keep in mind that it's normal for almost all parents to worry about what their toddlers eat.
As babies they are rapidly growing - fastest rate of their lives (double their birth weight by 5 months and triple their birth weight by about 1 yr old) - and that slows down as they hit toddler stage.
They are walking - which burns up energy and slows down weight gain - but their appetites switch gears a lot.
It'll rev up for growth spurts and drop down to almost nothing in between.
Their stomachs are bout the size of their fists - so they fill up fast and need in between meal snacks.
You just have to make sure you offer healthy choices - and sometimes she'll eat it and sometimes she won't.
When in doubt - keep a food diary of what she eats over a weeks time.
Most toddlers do pretty good - better than their parents think they are.