Former President Jimmy Carter admitted Monday he did not expect to live more than one month after his cancer diagnosis last year.

"A year ago, I didn't think I was going to live for two or three weeks," Carter told attendees at a Habitat for Humanity event in Memphis, Tenn., Monday.

The 91-year-old said when he and his wife Rosalynn found out he had skin cancer last fall, they chose to put on "kind of a false, optimistic face" when he visited fellow Habitat for Humanity members, so not to scare them about his depleting condition.

Carter told members of his church, Maranatha Baptist, in Plains, Ga., on Sunday he had "had a feeling" of "despair" at the onset of the ordeal.

It's been nearly a year to the day last Aug. 14 since the former Democratic president announced he had had a mass removed from his liver and was being treated with Keytruda, a new cancer drug. The fall months were difficult for Carter, forced to rest and take time off from his busy schedule with the housing nonprofit.

But a year later, Carter said he feels "pretty certain about my cure."

The Carters will continue to work with the Habitat for Humanity. They are currently helping build 19 new homes for low-income families in Memphis.