¿qué?

(Corrects in Spanish) *Sí

[Apologises in Spanish] lo siento

(As my Spanish teacher would say) tú no sientes nada

[Corrects your teacher] Tú sientes nada o Tú no sientes
If your teacher says that then it's a double negative so you feel everything

(Corrects you in Spanish) it actually is grammatically correct in Spanish