I'm reading right now 'How to talk so kids will listen ...' (i can recommending it to anybody, it opened my eyes to a completely different way of talking to my DD) and trying to practice and behave accordingly. It works some times, it doesn't work some other times, sometimes i loose it and make mistakes, it's tough until we all learn, both me and the kids. But there comes the time when all is too much. The time when i need to just stop explaining, reasoning, listening to them throwing in tantrums, the moment i feel i can't take any more. Is it wrong to shout 'that's enough' with no explanations just MY need to stop all these and trying to keep sane for the next few minutes? I had moments when i tried not to do it and i kept it inside and, hell, that eat me from within for quite a while, quite a long while
DD has such a negative reaction to it i started to be afraid to do it any more .... grudge, anger, playing with her dolls and screaming at them all the time (imitating my 'raising voice' but in a horrible histerical tone all the time) .... i decided for a while to swollow my feelings and just keep quiet. It didn't help much, her attitude was just the same ..... and i lost my sleep :D
Maybe you could nip your frustration in the bud just before you shout so you can tell her 'that's enough' without raising your voice. I think with really young children you can't really expect any empathy but from about 5, if you have tried to listen to their needs and reason etc and it is just not going anywhere you can say 'this is driving me crazy, I need some peace to calm down'.
As far as I remember the book has nothing against getting cross and showing it, in fact it encourages it - iirc it suggests using words like 'I'm furious!' so I don't see why 'That's enough' is a bad idea. Last week when ds1 had led me right to the end of my tether and was whining in the car I said very loudly (OK shouted ) "Be quiet! I don't want to hear another word - I'm too cross with you s don't speak to me till I've calmed down." It did work. I think that was within the spirit of what the book says. I reckon it's important that they know you're not an automaton and what they do/say has an effect on your emotions.