Ds's behaviour is driving me to despair at the moment; every time I leave the room, within 30 seconds I hear dd start to cry and when I ask him if he has hurt her, he just says "Yup". This week I have caught him a) kneeling on her back b) pinching her neck and c) using her back as a stepping stone. Every time I make sure he says sorry and I've used a naughty room and this morning I put him to bed for some time out. Nothing seems to have any effect and if anything it's getting worse. He has also been really unpleasant with friends we've had round this week, yelling "Mine" and snatching whenever they play with anything and whenever I challenge him, he will get angry and either throw whatever is in his hands across the room, or hit/kick me or the friend.
I'm getting really really angry with him about all this, and lack of sleep because of dd not going through the night is really making everybody even more miserable and because I'm so tired, I can't think creatively enough to distract him out of this behaviour. I have said some really horrible things to him this week because I'm so fed up with him - so actually am not liking myself much either. Any tips?