It make me feel happy.

It makes me feel unhappy.

It doesn't make me feel happy

It makes me feel unhappy.

It makes me feel upset.

It doesn't make me fell happy.否定句就需要否定词not，仅仅把happy改成unhappy的否定形式，考试是不会得分的。但是如果是日常交谈，或者写作文，而不强调要有not的时候，就是对的。