LO not eating

My LO used to be the best eater. She would eat 5 meals a day and pretty large portions. I used to joke that she ate more in a day than I did. But we recently traveled and she is sick with a cold. Now she hardly eats anything. Maybe a bit of oatmeal for breakfast, 4-5 bites for snack, lunch, and dinner. Honestly what she eats now in a full day would be the same amount of food as 2-3 meals before she got sick. Anyone else have this happen? Is it just because she’s not feeling well? She also feels lighter when I pick her up so I’m sure she’s lost a bit of weight.