I'm ecstatic*

Used as a reaction to smth you are completely unimpressed with or unhappy about.

“Are you excited about your in-laws moving into your neighborhood?”

“I’m ecstatic.”

*Some common phrases may be used in a sarcastic way. It’s usually the context (or/and intonation) that gives away what the speaker actually means. Sarcastic words are not to be interpreted literally; they convey the opposite meaning of what seems to be said.