What will the creature do next? How does he feel about it?

I'm not sure what you mean here. Do you mean at the end of the novel? After weeping over his creator which he has just killed, the creature tells Walton about his pain and anguish. The creature disappears into the darkness. What happens after that? This depends on you. In one version I have him making a lot of monster movies in Hollywood making lots of money. In a more realistic version I have him killing himself. Really the creature isn't such a bad guy/creature. All he wants is what we want, to be loved. The creature can't have that. He also regrets what other people's cruelty has made him become. There is nothing left for him.