Donald Trump 's new campaign manager, Kellyanne Conway, told CNBC on Monday the GOP presidential nominee has had a rough two weeks, but Hillary Clinton 's campaign made a mistake and "put her into hiding."

"Scarcity benefits Hillary Clinton. If you don't see her, you forget she's running. And you think the entire election is a referendum on Donald Trump," Conway said on "Squawk Box."

Conway questioned why Clinton has not held a press conference in more than 260 days. "Why is the press OK with that? And they truly are," she asserted. "Two hundred and sixty days, you could have had a baby by then."

Last week, Trump made changes in campaign leadership, promoting Conway to campaign manager. Stephen Bannon, co-founder of conservative Breitbart News, came on board as campaign CEO.

Paul Manafort, who had been running the Trump machine, resigned Friday.

"We'll look back at these two weeks ... and say: 'Why in the world didn't Hillary Clinton's campaign totally put us away,'" said Conway. "I think they made a grievous error by not having her go over to the Middle East and meet with the troops or make major policy speeches."

"The next two weeks we're going to be talking about the polls tightening," Conway predicted, saying the rough patch in the polls "lights a fire under us."

Last week's speech, in which Trump said he regrets comments that "may have caused personal pain," shows America what the candidate is really like, she said.

"Those of us who know him see consistently [a] guy who is compassionate, who can be humble, ... who enjoys himself on the trail," she said. "He gets oxygen from at being at these rallies [and] from giving these speeches."

Contrasting Trump's approach with Clinton, Conway said the Democratic nominee "looks like she's not happy to be out there" campaigning.

In recent days, Trump has not changed or softened his tough stance about building a wall along the U.S.-Mexico border or finding a fair solution to undocumented immigrants, Conway said.

"He doesn't deport 11 million people in his plan," she said. "We need a fair and effective way to deal with the 11 million [undocumented immigrants] who are here who live among us; at the same time protecting American jobs ... securing our borders."

Trump's campaign reboot is about "substance [and] about the issues," Conway said.

But right after Conway's CNBC interview, Trump lashed out at MSNBC's "Morning Joe" co-hosts Joe Scarborough and Mika Brzezinski.

Trump also alleged a romantic relationship between Scarborough and Brzezinski.

Disclosure: CNBC and MSNBC are part of NBC Universal, which is owned by Comcast (CMCSA).