Hi there - It's highly likely you have lost the yeast if it froze solid. If you really wanted to be sure, you could always thaw it, wash the yeast, and make up a small starter batch of wort to pitch the yeast into it to see if you get any fermentation. Much like you would a starter. If fermentation takes off, you could let it go to completion and store the yeast as you would if it didn't freeze. You're only risk is that you end up wasting some time because the yeast is in fact dead. I would try it - you have nothing to lose but a little time.
Regarding your beer - I wouldn't worry about. I'm willing to bet it's still going to taste great and you won't get any off flavors. There have been many brewers who have accidentally turned there fermenting wort into a slurry by accidentally freezing it during lagering and they still ended up with great tasting beer in the end! So, relax, don't worry, and enjoy that holiday homebrew!