9 week old refusing milk. Help!

Hally • Mommy to Rhowen Elizabeth Kai 💕

My 9 week old normally would drink 4 ounces every 3-4 hours then it went down to 3-3.5 every 3-4 hours but as of tonight she drank one 4 ounce bottle and one 2 ounce three hours apart. She's starting to eat less. I'm a ftm and I'm so worried and stressed out. Not to mention I'm running off of 3 hours of sleep from last night 😅