My son is 16 months old. Usually lovely and very active. Always on the go, walked at 9 months but is yet to say his first word. We've been out all day, he should be knackered, but for some reason he's awake and incredibly hyper. He's banging his head off the radiator and laughing, kicking me if I go near him, headbutting me, slapping my face, spitting at me, screaming and laughing after every minute or so and being generally extremely hyperactive. It's bizarre and I've never seen him like this before. He's now starting at me just saying rarararara repeatedly. Honestly it's like he's been swapped with a child I've never met before. Has anyone experienced similar?