My little boy is 2 months old and has struggled with weight gain since he was born. We've gone for weight checks pretty much every week since he got home from the hospital and sometimes he will gain enough that they aren't concerned but most of the time he doesn't. He didn't get back above his birth weight until he was 7 weeks old and now at 9 weeks he's a little over a pound above that. We are mix feeding giving formula and bf. His pediatrician wanted me to start giving him 3 ounces of formula every time rather than 2 but when I started doing that he started spitting up .5 oz- 1 oz every time. I'm really scared that something is wrong. The doctor said that if he doesn't gain enough by Thursday that they will do blood work. I just don't understand why he's not gaining. He's not lethargic or sleeping all the time, he eats normally, he's super alert, and he's constantly moving. He doesn't seem sick or anything so I don't know why he's not gaining.