NAB sweetheart im so sorry your having such a rough time.
I dont know how i do it, but if my DD is acting up i switch to what dp calls 'robot mode', unemotional, firm and resilient..i dont ask i order and it works(with my dd) i show no emotion and deal with it 'like a robot'..maybe its not the right way to go, but its a trick i began when i was on anti d's and also found them to be a pile of crap, i tried every type available but none helped me.
In the end i went to counselling(past probs as well as PND) and somehow(dont know how) managed to work through it with no drugs.
So sad that homestart couldnt help, accept any offer of help, you wont 'bring anyone down' you will feel so much better actually having a talk a cry a shout..honestly, so friend or counseller, i think thats what you need.
Does Dh know you feel like this? can he help out more?
As hard as it is to understand you children dont mean to upset you so much, theyre at those ages were they 'try it on' without fully realising their consequences, unfortunatly we have to be thick skinned enough to not let it get to us, but is does as thats not something they teach you at antenatal classes..i really hope you manage to get a break today and they ease up on you...can yo get them to park after school?, get them out in fresh air, take some junk food, theyll have fab time and may be a little more appreciative of their wonderful mummy?