You were upset about him because there was a misunderstanding between the two of you. You were pouting and frowning when you were around him and yet he focused on his work more.

The two of you were on the sofa. He was working and you were pouting. Alex then looked at you and spoke.

"I told you, it was a misunderstanding. End of discussion."

He spoke before he got back to his work.

You then left and decided to go to a party. You went home at midnight just to annoy him.