My ds is 3 weeks old today he weighs 11lb 14 oz is a big baby . I'm feeding him cow and gate infant milk and through the day he is taking 4 oz every 3 to 4 hours . But at night he's not finishing a bottle and waking up hungry every hour half 2 hours. I'm so tired don't know where I'm going wrong? What can I do to get a better routine,?