What can I do if I really want to dance again?

I would ask your teacher if/when she will be back, and ask her is she could recommend somebody else to help you guys while she is away. Tell her what you just told us about your concerns for your group. I don't know if you guys are at a studio, but if you are, wouldn't there be another teacher there that could help you? If you aren't at a studio, I recommend you all joining a class at a studio together. That's if your teacher doesn't come back of course. You are very right when you say that it's hard to learn new stuff without a teacher!