Baby eating less ??

My 7 week old has been eating 4oz every 3-4 hours for the past 4 weeks. All of a sudden, this week, she hasn't been finishing her bottles. She's been drinking 3/3.5 and it's a struggle to even get her to drink that much. Last night, she drank 3.5, now (5 hours later) she barely drank 2. She doesn't seem uncomfortable ... But I'm not sure if this is normal? Anyone else going through this?