This World We Live In by Susan Beth Pfeffer
About: It's been a year since a meteor collided with the moon, catastrophically altering the earth's climate. For Miranda Evans, life as she knew it no longer exists. Her friends and neighbors are dead, the landscape is frozen, and food is increasingly scarce. The struggle to survive intensifies when Miranda's father and stepmother arrive with a baby and three strangers in tow. One of the newcomers is Alex Morales, and as Miranda's complicated feelings for him turn to love, his plans for his future thwart their relationship. Then a devastating tornado hits the town of Howell, and Miranda makes a decision that will change their lives forever. (from amazon.com)
I think I get in these weird book phases. First it was end of the world books, now I seem to be finishing book series. Maybe because I'm dying to read Mockingjay (that I still have no money to buy, its sad I know). I don't know why I haven't got this one earlier, maybe cause I've had so many other books to read, but I finally requested it from the library and will be reading the last book in The Last Survivor series very soon!