SAN JUAN, Puerto Rico - Puerto Rico is pleading for help six days after Hurricane Maria hit the island with a vengeance. Food, water, gasoline and electricity are are all needed desperately by the island's nearly 3.5 million residents.

San Juan Mayor Carmen Yulín Cruz is at her wits end trying to find help, CBS News' David Begnaud reports from the capital city.

"I know that leaders aren't supposed to cry, and especially not on TV, but we are having a humanitarian crisis here," Mayor Cruz told CBS News.

Now, some survivors are facing a second brush with death.

Like other hospitals on the island, the Maestro has no power. A generator powers lights on two floors and there is no air conditioning.

Jesus Garcessoto's cancer took a turn for the worse the same day Maria hit. His wife, Lyssette, described the difficulty.

"I try to help him you know in the nighttime … trying to open the doors, open the windows. It's not easy," she said.

About half the island has no water, and there are excruciating waits for essentials. While FEMA says it has the supplies it needs -- with more aid arriving -- there are huge challenges to deliver it.

Alex De La Campa, FEMA's director for the Caribbean, outlined the problems he faces.

"Because we are an island, there's no trucks or roads that we can bring commodities," De La Campa said. "So, everything had to be brought. We need to bring in everything via airplane or barge."