Hello Doctor, my baby is 5 and half months old .. he rollovers, moves front, plays with toys, follows moving object or if I'm walking in room .... one thing I have notice is he actively plays with me, laughs,smiles by looking at me while he is laying down on his back like when I'm massaging or while breastfeeding or while my husband is holding him... But when I hold him up he doesn't look at me... He starts looking sideways or down or looking at something colorful.. I find it strange Is this normal please respond