That's the problem. There really is nothing you can do. You can hope that it is only temporary but you really don't know for sure. When it actually happened to me on Monday, my first reaction was to get on the phone and call the web host but for all the time I spend on hold, the problem could be fixed already.
My solution was to jump on twitter. There I found hundreds of website owners having the same frustration that I was having but with a twist. Some were handling in a better way, almost humorously. The jokes and light-hearten comments lifted my mood and left me with a chuckle.
Turns out the site was down for only 30 minutes or so. Not long enough to do any damage.