The 75-year-old Christian singer said he was left physically and emotionally exhausted by what he's described as a "two-year ordeal."
He was told he would face no further action following an investigation into allegations of historical sexual abuse.
Sir Cliff says he's undergoing medical tests in an attempt to determine whether the strain has left him suffering from any long-lasting ill effects.
It began in 2014, when he was on his farm and vineyard in Portugal.
He received a call saying police officers had a warrant to search his apartment in Berkshire.
However, he was unaware of what he had been accused of until coverage of the police raid appeared live on television, after what's thought to have been a tip-off.
Speaking to the Daily Mail, Sir Cliff said: "That was my introduction to what they were doing and how it looked on the screen.
"It was really terrifying, really horrible, and of course that's when I discovered what I was supposedly accused of.
"I didn't know how I could face the future or face my friends or face my family. I was in tears.
"I was on my knees in tears in the kitchen. I was thinking: How can I get out of this? How can I ever climb out of this hole?
"Somebody got me to my feet and said: 'You've got to stand up, you are not guilty, hold your head up, you can do it.'"
The case against Sir Cliff was dropped earlier this month after a review of the evidence by the Crown Prosecution Service.
The singer says he's forgiven his accuser, and said: "He probably doesn't even know I've forgiven him, but me forgiving him is not as good as God forgiving him.
"But only he can ask for that forgiveness."
South Yorkshire Police have since apologised over their handling of the investigation, during which Sir Cliff said he felt like he was being used as "live bait" for accusers with spurious claims.
He called on the BBC to follow the police for what he described to the Daily Mail as "shameful" treatment.
A spokesman for the corporation said: "We applied normal editorial judgements to a story that was covered widely by all media."