I have a one month old son, and he was primarily breast fed until recently. He has always ate from a bottle due to latching problems since birth. I was not producing as much milk as he needed, and eventually I went to the pump and nothing came out. So he is now on his second day without any breast milk and he really seems to be struggling. He has never been partial to the taste of his formula (similac advance), and now appears to be suffering from extreme constipation. He has never been colicy, but last night he screamed for 2 1/2 hours, and again for an hour today, and mommy couldn't soothe him. I called the pediatrician, and they said its because I was feeding him too often and too little (I have always fed him when he wants to eat which usually falls between 1 1/2 and 3 hours and 1 1/2-2 ounces), and that I need to start feeding him 4-5 ounces every three to four hours. I attempted this last night for the first time, and he seems miserable, I feel like I am starving my son. Any suggestions? I feel so guilty and helpless.