What is this behaviour all about....driving me potty!

For the last few days DD have been acting up, i have no idea why, she is normally so good, and kind and quite easy and fun to be around. but she has become frustrated and abit agressive. hitting, trowing things, will have a melt down, hit herself in the face, cry, the two seconds later is running around laughing wanting to play.
I basically ignoring her behaviour, apart from telling her not to throw/hit etc when it gets a bit out of hand, i just come close to her and explain its not right and it upsets mummy. she agrees but does it again soon after.
We are giving her stacks of attention so i dont think she is attention seeking. shes eating pretty well and doesnt have any numbers in her diet. She has been more tired than normal by the time her afternoon sleep time comes around but this behaviour is the same from sun up to sun down.
I have always been so worried about handeling her behaviour wrong and creating more problems. she is an extreamly good communicator and have always got over these issues by talking to her, but i think she needs more than that now!?!?!?!?
sorry for going on and on. probably just normal 'terrible twos' and i just need to suck it up. i just hate seeing her so ..... different! :(

:bump:

Bec, my DD2 is nearly the same age and is going through similar, it really is their age, my DD1 went though this too. She is testing the boundaries with you, DD2 gets cranky and throws toys etc and when she really gets upset tries to hit me or have a full tantrum hands and legs on the floor everywhere or throwing everything out of her cot. When she does this normally shes showing me she is frustrated that something isnt working for her (a toy) or shes bored, or feels like she cant do something herself. Also shes been grumpy due to her eye teeth coming through. Is your DD getting any teeth or 2 yr molars cause they make the girls really grumpy. Also lately DD2 wants more sleep when DD1 is at kinder 2 days a week DD2 sleeps from 11am - 2pm, but when DD1 is around she doesnt get that much sleep during the day cause they play together and share the same room. What kind of activities does she like to do? I find that drawing or reading relaxed DD2, and dancing to a song gets rid of her grumpiness and changes her mood. Does she have play time with you and free play when she plays with her toys by herself? I dont know if I have been much help. Maybe she may be coming down with a cold if she needs more sleep?