My baby is 9 weeks 5 days now and up until the last few days, he ate really good. At 1 month, ate 4oz each feeding and 2 months 6oz each bottle. Now all of a sudden, he only finishes the bottle for 2-3 feedings a day usually in the morning and at night. During the entire day, he doesn't act very hungry and drinks only 3-4oz and that's with alot of work from me to get him to drink. Is this normal and when should his appetite return to normal? Should I be concerned? He just had his 2 month checkup Monday, could the vaccines maybe have affected his appetite? I don't remember how his appetite was on Sunday.