I am so sorry that you have to put up with so many stressors all at the same time....obviously you need immediate relief....i have seen that some people have the knack of being cool even in hostile surroundings...take your husband for example..he can keep cool in the same house ....i suggest you leave the kids to their own devices,dont intervene at all...when things get really loud,go to your bed room &rest for a while...let them solve their own problems...try this for a while...you seem to be a perfectionist,but let this habit take the back seat for some time & see the results...the mess in the house does not matter...what matters is your sanity.....if every one is being selfish you also tread the same path.
I am sorry about your husband..mine too had stents put in...so i know how it feels...hope he recovers fast.Have patience ,these days too will pass.
How about reading my post "Beat the blues" http://jeeteraho.blogspot.com