Sick toddler

I feel so helpless. I don’t know what to do. My 2 years old daughter is getting over a cold and now currently has an ear infection. She’s on medications but she won’t eat and is barely drinking. She’s already a picky eater so it bothers me even more on whether she’s getting enough nutrients. Her pediatrician told me last week that she’s fine and blood works are okay too. She’s being lethargic and seems out of it. Is that normal when they are sick or I should bring her to the ER?