My cat just had kittens and isn't eating her food. What should I do?

Just like humans, there are many reasons Lana may not be interested in food and it is impossible to know without a physical exam. It's possible there are still kittens inside the uterus. Uterine infections are also possible. Unfortunately, both of these can be fatal without treatment. It's also possible this is something like a less severe infection but one cannot know without an exam. Have her examined today and bring the other kittens with her. If she is not feeding the kittens, you will need to take over. Here is a link about normal feeding:
https://www.petcoach.co/article/care-feeding-of-queens-kittens/

Here is a link about assisted feeding:
https://www.petcoach.co/article/how-to-raise-orphan-kittens/

Additionally, have Lana spayed when the kittens are 12 weeks old. Spaying pets has significant health benefits, helps to control the problem of pet over population and Lana may have up to 30 kittens in a year. That's a lot of cats to care for. Please feel free to post and additional questions. Best of luck.