You’re not? No, I’m not.

From Twitter:

From Twitter
Look:
A: You’re not going?
B: No; I’m not. I have to wash my hair.

C: Is it Thursday?
D: No, it’s Friday.

E: Are you hungry?
F: No.
E: Really? You’re not?
F: No. I’m not.

Try:
G: Are you happy, now?
H: No.
G: You’re not happy?
H: __, I’m not; the food is terrible.

*Yes
*No

Answer and Explanation:
The answer is ‘No,’ because we do not confirm a negative (for example, I don’t, it isn’t, we won’t, it doesn’t) with a positive (like affirmative, yes, uh huh).