It's impossible to handle that I guess.. Maybe you can, but just for a few days, after that you will probably be angry and you will try to find a new job :)
But what can help you is to have a good sleep and to do some activities after work (sport, music, drinking)... Whatever makes you happy..
@hellwd when do you face such situation generally, can you anecdote some instances of context switching you faced.
I am trying to find out the common reasons for context switching. Please comment how often you face this issue and why. And if you have any trick to avoid any of these, please do write that as well.