Kate said: "I've had days when, if I wasn't crying about Madeleine, I was crying from the letters and messages people have sent to us. It has helped so much."
Her lowest moment was the night her eldest daughter went missing in Portugal on May 3. She said: "A lot has happened since then. Sometimes, the most trivial of things can bring you crashing down."
Mrs McCann also revealed she and husband Gerry are trying to give their twins, Amelie and Sean, as normal life as possible. She told the Leicester Mercury: "Something carries you through. We have Sean and Amelie of course. We are there for them. We tell them that she is missing and that everyone is looking for her. And that's the truth."
The couple have thanked the people of Rothley and Leicestershire as a whole for their continued support.
Mr McCann said so many well-wishers had written to them that, until recently, they had to collect their mail from the post office in their car. There would be three crates of letters and cards awaiting collection every day, he said.
Mr McCann added: "We want to increase awareness, get back to basics if you like. Target specific areas with pictures and billboards and messages. We want to refocus the coverage."