Twins 1, Mummy Nil! Why Won't They Eat?

For a while now, feeding the twins has been fairly easy. Breakfast, lunch and dinner, along with a fair few snacks all down the hatch in a nice and timely manner with no, or mostly no issues... Until now!
For some reason feeding time is now a nightmare. Food is refused, heads are turned away, food is thrown on the floor and occasionally at each other or at me... It has become a battle to get them to eat anything... Apart from sausages and chicken breast (my twins, it would seem, are definitely not vegetarians)!
I'm not sure what I am doing wrong, or what has suddenly changed, but it is getting a bit frustrating and also they must be fairly hungry and that is awful as I hate to think of them with grumbly tummies. 
I feel a little bit tense and frustrated today :( hmmmm!