Stand back instead of fighting back. Smacking will simply encourage them to hit out. Make sure they understand good behaviour and reward them for it. If things get impossible, take time out. Make sure they are in a safe environment, close the door and have a cup of tea in the next room.
Every parent needs some break from their child.
Get someone in the family or a babysitter to look after them and find some space for yourself. One of the biggest problems is that toddlers are masters of psychology. They know how to wind up their parents and get a reaction. Learn a few tricks yourself. Visit our extensive Ask the Doctor library of all previously asked questions and answers covering a wide range of topics.