Iran said that the US will regret this action forever of what they do. Iran has got a huge oil reserve and again, this is happening just like what they did with Afghanistan and Iraq.
I don't think Iran expected an attack from USA so soon, so they were caught by surprise, and the lack of innovative and immediate actions from their side right now displays that.
Everyone didn't expect that the US will do that attack. When it was thought that they're only telling things but no, they've joined already with the Israel for this war.