Days and nights mixed up

I think my baby has her days and nights mixed up. She is up every two hours right on the dot at night time but during the day she can go 3 to 4 hours without feeding. And I’ve also noticed when I get done feeding her at night time she does not want to go back to sleep when I turn the light off if I turn the light back on she will go to sleep. what is the best way to get that switched around?