It's all I can do to stop myself from checking the website every 5 seconds!
I know what this phrase means, but does anybody know where it came from? On the face of it, it doesn't make any sense. This phrase stands on its own, and means "I find it difficult not to check the website every 5 seconds", so what, exactly, is all the speaker can do to stop himself from checking? What does the "it" stand for?