My DS is almost 4 months old. He holds his head up well when I am carrying him, and is OK when being held in a sitting position. I am just a bit concerned that he seems to have trouble controlling it. If he turns to face a different direction his little head bobs about quite a bit. He isn't quite strong enough to sit in his Bumbo seat - his head still moves about a lot making him uncomfortable. Anyone else experience the same and should I be concerned?