A child up to 1 year old can not yet indicate that something does not suit him, other than through sounds, crying, body movement. At the beginning it was difficult for me to read when and what makes the toddler feel uncomfortable. I watched my Frank carefully so as not to duplicate activities during which he demonstrated "rebellion".
During pregnancy you were preparing your child for the arrival of a sibling. You thought the tot understood what was going to happen, and that by stroking and cuddling your belly he showed his feelings towards a baby brother or sister. Therefore, why does your older child begin to behave odd when you come home from a hospital with an infant?