Yes, it is a bummer. Life happens. Hope your recovery is fast, but take the time to get healed 100%. You can practice the form in your mind, self defense technique, even sitting in bed, down block punch etc. Maybe your instructor can show you some more blocks--like inside middle block and high block as well as they will be coming up soon. And when you are better do what Lisa did and just observe, you do learn alot. I did that as well, when I was out with a bad knee more than once. And you can always stop in here...
TW