my 5 month old is having his hunger strike 'again'. Once every week or so he would have a day or two when he would refuse milk for as long as 8 hours. As a 17 pound boy, he is already taking less milk than most babies I know (5 x 4 or 5 ounces). Lately, he develops a habit of skipping the entire feed. He would turn his head away or arch his back. And even after 8 hours without milk, you would think he'll finish the whole bottle in his next meal, but NO, he would stop after he has his 3 or 4 ounces. I noticed that he is peeing much less on such days. He is playful and seems happy. Haven't weighed him for over a month so not sure about his weight gain progress. Should I be worried?