(CNN) President Donald Trump lashed out at acting chief of staff Mick Mulvaney during a Situation Room meeting with Democrats, including House Speaker Nancy Pelosi and Senate Minority Leader Chuck Schumer, earlier this month, a White House official said Sunday. According to the official, Trump cut Mulvaney off toward the end of an unproductive meeting on re-opening the federal government, as Mulvaney was attempting to negotiate up from the $1.3 billion Democrats offered the White House. "Stop, stop, just stop -- What are you doing? You're f---ing it all up, Mick," Trump said, according to the official who was in...