Remember to breathe.

It'll all work out. I promise. There are far more people in the world who are financially unprepared for a baby than those who are. Try your best not to take on your sister's situation and focus on your own. The baby won't be born tomorrow...nature gives us those months of pregnancy in order to prepare for bringing a baby into the world. It doesn't sound like you'll have to move really soon. You have time to figure out how you want to live you life, where, and with whom.