New York(CNN) President Donald Trump was incredulous Tuesday as he sat in Trump Tower and watched House Speaker Nancy Pelosi announce she was launching a formal impeachment inquiry against him, sources familiar with the moment say. Sitting in the same building where he launched his long shot presidential campaign four years ago, Trump said he couldn't believe it, he later told people.

He had felt confident after phoning Pelosi earlier that morning. The drive for impeachment in her caucus had ramped up amid reports he pushed the Ukrainian President to investigate Joe Biden, and Trump was hoping to head off a clash. He figured he could de-escalate tensions by speaking with her directly.

It was after that call that Trump made the decision to release an "unredacted" version of the transcript of his July call -- against the advice of aides such as Secretary of State Mike Pompeo, who warned him it would set a risky precedent. Trump wanted to undercut the argument from Democrats that he acted inappropriately, he said, and felt he had nothing to hide.

But when the announcement he would release the transcript did little to quell the growing calls for his impeachment, Trump was in disbelief.

Democrats immediately argued that it wouldn't be enough. They also wanted to see the whistleblower's complaint, which had been found urgent and credible by the inspector general for the intelligence community and was mandated by law to be handed over to the intelligence committees. Administration officials began working out a plan to declassify and redact the complaint so it could be turned over too, all in the hope of easing escalated tensions with lawmakers.

After Pelosi's historic announcement, Trump immediately began lashing out, accusing Democrats of distracting from his successes at the United Nations General Assembly and arguing it was just "more breaking news Witch Hunt garbage."

But people close to him said he is not welcoming this impeachment fight. The President who keeps a careful watch on his approval numbers was unhappy.

A source close to the White House who routinely speaks with Trump confirmed he does not want to be impeached. Despite the argument that it could help him politically, Trump, according to the source, has worried about the possibility of being impeached for nearly a year, dating back to the weeks that followed the November 2018 midterms when Democrats won the House.

This also isn't the first time Trump has misread Pelosi. He also told aides he wasn't that worried when Democrats won the House after the 2018 midterms because he thought they would be easier to work with than some of the Republicans he had been forced to deal with, like former House Speaker Paul Ryan. Six committees are now investigating Trump, ranging from his tax returns to his policies in office.

Aides and allies of the President plan to argue that Democrats have wildly overreached here.