My boy is 6 weeks old and being breast fed. He feeds every two hours right through and sometimes struggles to wait that long. He is putting on 1 lb per week. We are giving him 1 bottle of formula per night to get him used to it (very unsucessful at expressing) He will only take about 2oz of this and often still wants the breast. Last night he fed for 1 hour, both breasts and was still creating for more food. How do I know I am producing enough milk for him?