If her teeth are sore she might enjoy some cool yoghurts (petit filous or, hurrah, sugar free version by Yeo Valley) or even some ice cream. Those are high calorie. Avocado too. Spreadable cheeses on toast, crackers, whatever she likes to eat. Not high calorie but a favourite in our house is apple purée from the fridge (again nice and cold).
Would she enjoy helping prepare things? That might encourage her to eat a bit. If she's happy enough to eat biscuits or cakes, then try to come up with more nutritious versions of the same thing. I do carrot and apple cakes with no sugar, or sugar-free rice pud (in the oven) is also a good one.
I really wouldn't worry, Lauren, totally normal around this age. My LO2 seems to be living on air at the moment and it drives me bananas but I know there's nothing I can do to *make* her eat. So trying to redirect my frustrations elsewhere.