Angry and frustrated 2 year old

Hi there!

I have two beautiful children aged 3 1/2 years and 2 years old.. My 2 year old little boy has always been a fantastic little sleeper, as a new born we would barley hear from him as he would feed and sleep all the time. People used to comment on how lucky we got with him even if he was awake he was just so placid and calm. Then he turned 2 and he has all of the sudden turned into a very angry and frustrated little boy, he's constantly throwing himself around screaming and smashing his head against things to the point he's bruising, if anyone goes near him or tries to help him with anything he loses his temper and only wants mummy, he used to eat all his dinner now I can barely get him to have 2 mouth fulls. He's still sleeping for atleast an hour and a half to two hours through the day and sleeps through from 7:30pm-7am waking once every few nights but only wants me to go in the room and no one else but when he's awake I feel like he's constantly crying/screaming if he doesn't get his own way or if something doesn't work the first time and I feel like it's more then 'the terrible twos' he's hitting and gets angry if his sister even looks at him. When he's in a good mood hes a beautiful little boy but I feel that's hardly ever now and we can't even take him to the shops without him having a melt down about something and I can feel people staring at me... Has anyone else had these issues with their little one and what did you do to help?