My 19 month older constantly has his head on the floor. He'll be stood on his feet, bent over with his head on the floor and his bum in the air. He does it all the time. When playing, even in his cot. He'll stay like it for a while. He'll sometimes just stand still like it and sometimes walk forward and hit into things. It's so odd, google suggested potentially a warning sign for autism but he got a zero score on the online MCHAT tests. Can anyone advise?