Donald Trump's inauguration has many in Mexico bracing for the worst, as the man who promised to build a wall, talked about mass deportations and threatened to tear up NAFTA launches his term as U.S. president.

There are deep ties between the two countries — economic, but also personal — as families straddle the border, making lives on both sides. Last year, remittances sent from the United States to Mexico totalled a staggering $25 billion US and this year they are projected to reach $27 billion US, according to BBVA Bancomer, a Mexican financial institution.

Sara Martinez, an agile 72-year-old who is retired, but still holds down a part-time job as a janitor in a laboratory, says getting older is her biggest worry — but that fear is heightened when she thinks about how Trump's next moves could take a toll on her ability to make ends meet.

Martinez

Sara Martinez, 72, relies on money sent from her son in the U.S. for extra help on a tight budget. (Andrew Lee/CBC)

Martinez's son lives and works legally in Massachusetts and, while he struggles to cover his own family's expenses in the U.S., he does what he can to send money home to help his mom and dad, she told CBC News.

"You know as the years go by, and you get older, there are things you can't do anymore," she says. "I come and I go and I can move around right now. It worries me a lot that I won't be able to do things like I do them now."

If Trump makes it harder or costlier for her son to send the money back, Martinez doesn't know what will happen.

"We're getting by," she says. "My husband and I can cover a lot of our expenses ourselves, but there's never anything left over. There are things we just can't afford ourselves. Without that money I don't know what the future will look like."

Trump is probably the least popular U.S. President in Mexico since James K. Polk sent the U.S. Army to invade the country and seize territory in the 1840s. 

On Friday, as Trump was inaugurated, locals took to the streets in Mexico City to participate in multiple protests against the newest American president.

Trump inauguration protests in Mexico0:49

But the disdain and disgust were also directed toward their own President Enrique Pena Nieto, who many believe is incapable of confronting anti-Mexican policies.

"He can't lead his country, so how is he going to make ties with another country," says Anne Marie Buckle, a 23-year-old dual Mexican-U.S. citizen living in Mexico City. Buckle is a recent nursing graduate who has chosen to live in Mexico because she feels her skills can make a greater difference here than in the United States.

Buckle

Anne Marie Buckle, a dual citizen of Mexico and the U.S., is working in Mexico as a nurse. She's worried about Trump, but also has doubts about the Mexican government's ability to deal with what's ahead. (Andrew Lee/CBC)

Even though she's chosen to stay, she doesn't have much hope that Pena Nieto has a clear idea how to handle the new American president.

"If your country is falling down, how are you going to build it up trying to make ties with another country where you have no support system. None whatsoever."

Internal woes 

Many Mexicans were particularly upset when Pena Nieto dismissed his foreign minister Claudia Ruiz Massieu, one of the more popular members of his cabinet, and replaced her with Luis Videgaray, a minister he had fired last September.

Videgaray had been dismissed from his post after he invited Trump to visit the country when the now-president was still a candidate, a trip which angered many Mexicans. Editorials blasted Pena Nieto for not challenging Trump publicly during his stay, and accused his government of humiliating the country.

Videgaray has been welcomed by some and rebuffed by others. He may not have helped his case when in a meeting with staff at the Mexican foreign ministry earlier this month he conceded that he wasn't a diplomat. But in an echo of the new U.S. president, the foreign minister said he was ready to learn on the job.