I am also finding that he is more 'assertive' atm. Today he got cross at couple of things (ie not being allowed to touch the bin), cracked it and started whacking my legs (totally out of character) and whinging. He then got overwhelmed and started crying and cuddling my legs. Then we sat on the couch, cuddled until he calmed down. It's like he didn't even understand what had a happened either, maybe not understanding what he's feeling/thinking & how to express it.
We have had the exact same thing, my usually calm,happy boy has started getting so worked up, he wanders off to find something to throw, yells at tit a bit, then goes and picks it up again.
But he is a shocking sleeper, who has just started sleeping,so definitely something odd about this age!