well...is your lo feeding throughout the night? if so, how much, as this may be the reason why he will only take a little first thing in the day. also, maybe (i know he is only 3 months) he is ready for a little longer between feedings?...maybe stretch it to 3 and a half or 4 hrs and that way he will be hungrier and take more (i suggest doing this gradually 15 minutes at a time though). give him as much as he will eat, but if u are feeding him during the night, maybe u want to cut those down slowly, ounce by ounce, every few days so he will naturally be hungrier during the day and take more...btw he may be going through a growth spurt...if he hasn't already...but as the previous poster said - sometimes they are hungrier than others...