Chances are your brew will be ok. Where are you at in the process? If it was still fermenting you may have to add another pack of yeast because freezing the yeast will likely kill at least some of them but generally not all of them. Same is true if you are getting ready to bottle, there likely will not be enough viable yeast to carb so you will need some more yeast. If fermentation is complete and you keg and force carb then no worries.