We know that 'migrate' means to move. So since that, we need to add the -ing, and we know that we end up with the meaning "moving".
So migrating means moving from one place to another.
After Gregor has died and freed his family of his horrendous presence, they can now take a rest for a while and get back to their normal lives. Gregor had been a burden for them in every way, as he stopped providing for them because of his new condition. Because of him, they couldn't leave the apartment and find a smaller one. Because of him, they had to rent a part of the apartment. His unwilling transformation had changed their lives for the worse. Now that he's gone, they have a hope for a better life. They even start pondering on their daughter's potential marriage.
This probably means that something you had planned to turn out well, ended up going against you. The scenario flipped it's self around and you were so said "betrayed" by your own plan or game.
<span>The youngest answered him that the ants had at last discovered the doll was filled with honey and, streaming over the piano, had devoured it in a single night. "Since the hands and face were made of Mikado porcelain and were as delicate as sugar," she said, "the ants have probably taken them to some underground burrow and at this very moment are probably wearing down their teeth, gnawing furiously at fingers and eyelids to no avail."</span>
