At end of tether with every relationship in my life except for dh!

[twoandahalftimesthree]

I feel so exasperated, stressed, manipulated by everyone in my life- my children are a nightmare, everybody I supervise at work are a nightmare- I am really at the end of my tether and currently am holding the door shut on my dd after she has come downstairs for the millionth time saying she feels sick (there is nothing bloody wrong with her) why is she doing this- she is 11 ffs! I have put up with a load of shit from her and her brother and feel manipulated at every turn, constantly guilty and angry. The fact that I put up with similar shit at work just makes it even more galling. I know I have to change my behaviour somehow to get treated with a little respect and for the last couple of years I thought I was making great progress, suddenly over the last month every relationship seems to have taken a dive and I don't know why. I am normally a very strong person but I feel at breaking point right now.