How much BM does my DS need?

Krisnralph

My DS is 3 months and goes to DC for about 10 hours. I nurse him before he goes and he takes 3 4oz bottles at DC then nurses when he wants at home. At his 2 month checkup the Dr. told me he should be taking 4-6 oz. at a time. He seems satisfied with the 4 oz. at DC but am I underfeeding him? Should he be getting more? I am having a hard time pumping enough for the next day already. Also the Dr. said that he would start on solids at 4 months. Isn't this early? Thanks in advance.