Here is a review of the rules for Present Simple and Present Continuous:

Present Continuous

+	-	?	Short answers
I'm painting.	I'm not painting.	Am I painting?	Yes, I am. / No, I'm not.

Signal words: now, at the moment, this month, year etc., today

Present Simple

+	-	?	Short answers
I paint.	I don't paint.	Do I paint?	Yes, I do. / No, I don't.

Signal words: always, often, seldom, hardly ever, never, every ...